Based on the preorder DLC packs in New Vegas (and several mods along similar lines) these are a series of "starter packs" useful for specific character types.

They all contain at least one unique weapon and one unique piece of armor. The armors all have "enchantments" applied giving specific boosts to skills and attributes at the cost of others. They all also have several useful items relating to the associated character type (ie Prospector gets some skill books and junk, Escapee gets some prewar money, sniper gets some .308 rounds, etc...).

Most of them are not too overpowered or immersion breaking, but combining items from the different packs can lead to early overpowered status. This is intentional as the point is to pick one for a character build and get an early start on that character. If you want to combine the different packs and get a more full on cheat experience, go right ahead.

NOTE: NONE OF THE "MAIN FILE" PACKS ARE REQUIRED FOR ANY OF THE OTHER PACKS. THEY ARE TOTALLY INDEPENDENT.

The Escapee's Pack:

Overpowered: NO
DLC Required: NONE
Location: immediately outside Vault 101 on the scenic overlook. You can't miss it.
Weapons: a slightly better (particularly critical hits) version of the 10mm pistol, 10mm SMG, and police baton.
Armor: Vault Tec Security Armor is slightly heavier than vanilla and has higher DT. It also has buffs to small guns, melee, and AP plus a small rad resist at a cost of -2 Agility. Vault Tec Security Helmet buffs AP and Endurance at the cost of Perception.
Misc: chems, food, 10mm ammo, 100 prewar money

The Prospector's Pack:

Overpowered: Yes at very low levels (1-4) slightly at "mid low" levels (5-8).
DLC Required: NONE
Location: against the cliffs directly in front of Vault 101 before the water tower. See Pictures.
Weapons: The Prospector's Rifle (hunting rifle) and Scavver's Shiv (combat knife) have slightly increased damage, significantly increased critical damage, a 10% critical chance, reduced AP, and increased weight.
Armor: The Prospector's Coat has buffs to barter, carry weight, and repair at the cost of -2 Agility and has 8 DT bringing it in line with merc outfits rather than plain clothes. It also requires leather armor to repair. Prospector's Lucky Hat buffs Luck and Perception by 1.
Misc: 1000 caps, 3 Tales of a Junktown Jerky Vendor, 2 Dean's Electronics, 1 Lying, Congressional Style, misc junk, food, chems, and ammo. (NOTE: you should get at least some .32 rounds for the rifle but the ammo is mostly random).

The Master Trader's Pack (UNIQUE TEXTURES):

Overpowered: At low levels but in difficult location (with the Barter Bobblehead)
DLC Required: NONE
Location: In a footlocker marked "Master Trader's Footlocker" directly left of the Barter Bobblehead (in it's vanilla location) behind the workbench.
Weapon: The Executive (Lincoln's Repeater) is more powerful than base and has lower spread but a cost of AP and clip size.
Armor: The Master Trader's Coat buffs Barter and Repair by 25, carryweight by 50 and has 22 AR at the cost of -3 Agility. The Master Trader's Hat buffs Luck by 1 and Barter by 15; it also has 3 AR. The Wasteland Tinkerer's Goggles buff Repair and Science by 15 at a cost of -1 Perception.
Misc: This one only has some .44 ammo due to the unique and better items. There should be plenty of loot in that location anyway :)
Note: The texture is basically the same as vanilla but with higher dynamic range, making it unique. See Pictures.
THERE IS AN EASTER EGG ITEM IN "ANGEL'S" CELL.

The Sniper's Pack:

Overpowered: Slightly
DLC Required: NONE
Location: "Hidden" in the rocks by the broken overpass outside Vault 101 (see pictures for location.)
Weapons: The Longshot (sniper rifle... duh) is significantly more powerful (particularly criticals) but has a 2 round clip and is slightly heavier.
Armor: Sniper's Suit has slightly reduced AR, slightly reduced weight, buffs crit chance and AP, penalty of -3 Endurance. Sniper's Headgear has increased perception and small guns at a cost of -1 Endurance and has the lowered AR and weight as well. The Nonreflective Shades buff Perception and critical chance at a cost of charisma.
Misc: 100 .308 rounds, jet, mentats, and 500 caps
NOTE: There is no quest related to the Assassin's journal pages but have a look around Moriarty's office if you get a chance :)

The Megaton All Access Pack:

Overpowered: Not exactly. It's a cheat to get you established in Megaton VERY quickly but has no use in combat at all (though the armor does provide 8 AR instead of 2)
DLC Required: NONE
Location: Crook of the wall to the left of the Megaton gate. (see pictures)
Armor: Megaton Finery buffs +30 Explosives, Speech, and Barter at the expense of -20 Small Guns, Energy Weapons, and Melee. The Rediculous...ly Stylish Party Hat buffs Charisma and Luck at the cost of Endurance and Strength.
Misc: 10,000 caps, stimpacks and radaway
Note: This pack is specifically designed to make gaining and upgrading the Megaton house possible right away.

The Wild Wasteland Pack:

Overpowered: YES
DLC Required: ALL
Location: On top of the Red Rocket in Springvale. You need tcl to get it because it's a cheat mod. There is an easter egg there however, so worth it :)
Contents: A "heavily modified" Captain Cosmos toy raygun, 2 stereotypical pairs of glasses, a set of ranger grade very naughty nightwear, a pint sized slasher copycat's mask, the Katana of a man who would be king, a legendary bb gun, and a lead pipe implant (Wasteland 2 easter egg).
NOTE: The "implant" is a slightly overpowered lead pipe that is marked as a QUEST ITEM and therefore CANNOT BE REMOVED WITHOUT THE CONSOLE... cause it's an implant :) The console code to remove it is:

Player.removeitem xx001249 1

where xx is your load order FOR THIS PACK.

The Raider's Pack:

Overpowered: Slightly but with major penalties
DLC Required: NONE
Location: A gore bag inside the red rocket in the Springvale School playground (see picture)
Weapons: The Junked Up Assault Rifle is Much more powerful than the standard assault rifle, has a slightly higher but more predictable spread, has a larger clip, and has a higher fire rate. This is offset by a VERY quick rate of decay and a slightly higher AP cost. Vic's Vengeance (nailboard) does slightly more damage and uses fewer AP but also degrades more quickly (temporarily removed).
Armor: The Spikey Painbringer Armor (Raider Painspike) has slightly higher AR and has +30 bonuses to melee and small guns at a cost of -1 agility and -5 charisma. The Masque of Terror (Psycho-Tic Helmet) gives 20 to melee and small guns at a cost of another -4 charisma.
Misc: 5 of most non-stimpack chems, liquor, .556 rounds,
Note: The note pages in this pack contain a significant amount of foul language, it is a raider's journal after all.

The Outcast's Pack:

Overpowered: Yes though not quite immersion breaking
DLC Required: NONE
Location: In a half buried trunk by the intact car to the right of the 101... exit. *see screenshots)
Weapons: Overcharged Scrap Rifle (laser rifle) does significantly more damage but has a 12 round clip and faster decay (right now it's barely noticeable but I may do a version 1.1 with decay closer to the raider assault rifle). Champion Cyd's Fist (power fist) does slightly higher damage, way higher crit damage and has a 10% crit chance. It also reduces endurance and does minor leg damage on hit.
Armor: The Outcast Scrap Armor is "unpowered" power armor. You don't need PA training to wear it but it has slightly lower AR, is significantly heavier and carries a significantly higher agility cost (similar to NCR Salvaged power armor in concept). It does provide 10 rad resist, 3 strength and 10 unarmed damage. The Outcast Heavy Recon Helmet gives you 2 perception and 5% crit chance boost at a cost of 1 endurance. It also has slightly higher AR and slightly higher weight.
Misc: health and rad drugs, MFC ammo.

The Four Eyed Gunslinger's Pack:

Overpowered: Slightly and more than slightly unbalanced at low levels.
DLC Required: NONE
Location: Corner of the destroyed wasteland home in Springvale across the street from Silver's crash pad. (see pictures)
Weapons: The Steampunk Cowboy (laser pistol) has significantly higher damage and crit damage with a 10% crit chance and lower AP cost. It has faster decay and a wider spread to compensate. The Commie Freak Out Pistol (unique Chinese pistol) is automatic (low fire rate but you can leave the trigger squeezed) does more damage, significantly more crit damage, has a 33% crit chance but also at the cost of faster decay and higher spread. Annie (scoped .44) does slightly more damage and crit damage at a cost of slightly higher AP cost. The Kid (.32 pistol) does significantly higher damage but has a 0% critical chance and is a bit heavier.
Armor: The Gunslinger's Coat has slightly higher AR and weight, buffs +25 small guns and +5 crit chance at the cost of -5 AP. It requires leather armor to repair. The 4 Eyed Gunslinger's Specs (tinted reading glasses) buff +3 PER, +25 small guns, +10 energy weapons, and +5 crit chance at a cost of -25 unarmed, -10 melee and -1 CHA. The 4 Eyed Gunslinger's Dress (prewar casualwear works with both male and female PCs but backstory is female) buffs +10 small guns, + 2 CHA, +5 cirt chance at a cost of -10 to melee and unarmed.
Misc: Ammo for the guns (should be at least some for each gun but mostly random). 3 Guns and Bullets, 3 mentats.

The Wasteland Adventurer's Pack:

Overpowered: Yes, particularly at low and very high levels
DLC Required: Operation Anchorage, The Pitt, and Point Lookout
Location: In a crook of the rock by a burned out car on the road from 101 to Springvale, (see pictures).
Weapons: The Tayzor 9000 (Mesmetron without the mezz script). It does 3 damage as opposed to 1 with the mez, applies 1 shock damage, briefly paralyzes the target and temporarily debuffs their AGL, PER, and STR. It also has a 1% chance of an instakill critical on anything short of (maybe) a Behemoth. Deuce (double barrel shotgun) does slightly lower damage but significantly higher critical damage.
Armor: The Wasteland Roamer's Armor ("unpowered" tribal power armor) buffs big guns, explosives and fire resistance by +10 at a cost of -4 AGL. It weighs significantly more than power armor (though less than the Outcast Pack) and has 33 AR instead of 40. The Wasteland Roamer's Chappeau (stormchaser hat) buffs almost all non combat skills by 5 at a cost of -2 CHA.
Misc: Wyndmoor the teddy bear buffs luck and endurance by 1 at a cost of -1 charisma. This works like the Lucky 8 Ball where picking up and dropping the bear applies and removes the effect. Various junk and chems from PL and an anchorage trench knife (unmodified). This one has a longer "backstory" than usual but still just a note, no quests or anything.

Pip Boy Upgrade Pack:

Moved to its own mod page.

Planned Packs:

A doctor starter pack, a scientist/mad scientist pack, an enclave pack (or really anything that makes for a good pure energy weapons pack), and a merc pack.

Known Issues:

No items have been manually added to lists for perk bonuses. I will integrate this as it seems needed though they all use default animations and almost all use default ammo. To some extent, this is intentional as the weapons are more useful at the start of the game and (sometimes) become less so as you level.

Shameless Self Promotion:

Fallout New Vegas:
JOANA COMPANION
SKYNET COMPANION
EMILY ORTAL DOCTOR COMPANION
ASSASSIN'S ABODE

Fallout 3:
ANTAGONIZER COMPANION
THE VAULT DWELLER'S STASH
PIP BOY UPGRADE MODULES

Skyrim:
DRAGONBORN SKAAL HOME
CRAFTMEISTER GEAR