Overview:
This simple system allows for the player to commission delivery of any weapon mod for any weapon they currently hold at certain vendors - allowing for easier acquisition of weapon mods without relying on vendor inventory RNG, at cost of an extra fee to request the delivery.

I set out to create a middle-ground between that of the classic Fallout weapon modding behavior (talking to a specific NPC with the relevant weapon and having them give you back the modded version of it) and the modern item-based modding system, while also making it easier to find specific weapon mods, since load orders with a lot of weapons with item mods can result in it taking forever to find the one mod that you're yearning for.

Usage:

• Get close enough to one of the detailed vendors to talk to them, and press the "Grab" key (RS for controllers, Z for keyboards, by default) with a weapon equipped.
• A menu will pop up, asking you if you'd like to commission delivery of a weapon mod.
• The system will read the relevant mods for your currently equipped weapon, and display the price you'd need to pay to commission delivery of each mod. Select one, the cost will be removed from you, and it'll be queued for delivery.
  It doesn't matter if your equipped weapon already has mods attached to it at all.
• You can request three mod deliveries concurrently at each vendor. Once the timeframe for each commissioned mod delivery is up, and you return to the merchant and press "Grab" while looking at the merchant again, any mods which is ready for delivery will be added to the vendor's chest.
• Once the mod is delivered and transferred to the vendor's inventory, you'll then have to buy it from them as normal via the barter menu.
  This also means that once the vendor's chest respawns it's inventory, that mod will no longer be available for purchase, unless the chest's inventory happens to end up with one in the reset based on it's standard inventory -this is done to make finding weapon mods via standard vendor stock RNG still relevant and tangibly more appealing than simply commissioning all desired weapon mods, and to maintain Barter's relevance to the process.
• Each vendor has a specific set of weapon types they can procure mods for - for example, by default, the Vendortron can only get you Guns/Explosives/Non-Energy Big Guns mods. To check how long is left for each commissioned delivery, simply trigger the system again on the relevant merchant.
  A weapon's presence in the EnergyWeapons formlist overrides it's Big Guns status, and the system will consider it an Energy Weapon.

Merchants:
Vendortron - Guns/Big Guns/Explosives - Lowish/Moderate price, low delivery time.
Gloria Van Graff - Energy Weapons - Moderate price, low delivery time.
Torres - Energy/Big Guns - Cheap-ish, long delivery time.
Mick - Melee/Unarmed - Higher price, longer delivery time, but not many merchants offer Unarmed/Melee.
Boomers Munitions Manager - Explosives/Big Guns - Expensive, but very fast delivery time.
188 Arms Merchant - Explosives/Big Guns/Guns - Cheap price, long delivery time.
Khan Armorer - Explosives/Guns - Moderate price, long delivery time.
SINK - All - Fairly expensive, fast delivery time.
Comissary - All - Moderate price, very fast delivery time.

TTW:
Flak/Shrapnel - Guns/Explosives - Moderate price, medium delivery time.
Friday (The Pitt) - Guns/Melee/Unarmed/Explosives - Expensive, but one of the only Melee/Unarmed merchants in DC+.
Pronto - Guns/Explosives/Big Guns - Moderate price for everything except expensive Big Guns, very long delivery time.
Durga (BS DC) - Energy/Big Guns - Cheap, fast delivery time.
Uncle Roe (Canterbury Commons) - Explosives/Guns/Melee/Unarmed - High price, long delivery time, but you do not have to purchase the delivered mod via barter - the mod will be given to you directly once the delivery has been completed and you prompt the system via Uncle Roe again.
This is due to Uncle Roe not being a merchant himself, which requires secondary scripting considerations. Rather than opening the barter menu for Lucky Harith via script, I instead decided to add more incentive to visit Canterbury Commons, which is most appealing for low barter characters. Lucky Harith still gets the caps from the purchase though, because he's presumably the caravan merchant the mod is being procured from.

Customization:
Whether or not each relevant vendor provides any mods at all is customizable.
The price multiplier for the delivery commission for each mod type at each vendor is customizable.
There is a toggle to switch the delivered mod to be provided directly to the player instead of needing to be bought.

Requirements:
JIP LN, xNVSE, Johnny, the usual stuff.
ShowOffNVSE is required.

Installation:
Regular installation.
Please endorse and vote if you appreciate the mod.

Patches:
This is not a framework - extending this functionality to mod-added vendors will require manual extension of the system in the GECK, with specific scripting.
I have no current plans to patch for other mods.

Compatibility:
Fully functional with any and all mod-added weapons/weapon mods.

Bugs:
Please post bugs in the bugs tab, not the posts. I get a notification when bugs are posted, but I have too many mods to keep up on the posts on all of them routinely.

Future Plans:
These may or may not occur depending on whether I feel like implementing them or not:
Variable delivery time.

What about ___ merchant?
Hoover Dam Quartermaster - I don't want to bother gating his access to the system behind his speech check to supply you, at least not right now.
Blake - He's pretty generic. Doesn't feel right to have him included.
Carter/Hannigan - Hard to get a good supply chain as part of ostensibly a raider/thug group in a very civilized area of the world.
Chet - Lol no.
Cliff Briscoe - Doesn't feel particularly appropriate.
Contreras - Don't feel like bothering to block his interaction with the system if he goes to jail. Will probably add him when I feel like it.
Joshua Graham - You don't see him for long, he disappears once HH is completed, and his supply chain is limited.
Johnson Nash - Small fry.
Lacey - Why does she even sell guns? (That's rhetorical)
Mister Holdout - The man sells switchblades and that's practically it.
Miguel - Maybe, eventually. Probably just Melee and/or Unarmed.
Old Lady Gibson - Maybe, eventually. Probably just Melee and/or Unarmed.
Michelle - Tiny fry.
Alexander - Maybe, eventually. Ultimately he'll be completely less appealing than the GR HQ.
Dale Barton - This merchant sucks tbh.
Karl (The Family) - The Family is pretty secluded and doesn't have much trade access, so I don't feel like he'd be a natural choice.
Haley (PL) - Mostly trades with swampfolk, so I don't see how he'd have the supply chain to acquire mods on demand.
Panada (PL) - Limited access to supply chains, and I make balancing decisions assuming PL is a low level experience, so I don't really want to stretch supply chain plausibility to have her providing any mod in the game at a relatively early level.
Micheal Masters/Gustavo - They're not really merchants per se, they're just opening their armament stock to you for trade.
Moira - She doesn't stock very good stuff most of the time, so between her being (probably) the first merchant you have access to and her relatively bad stock, I don't want to add her to this system.
Smiling Jack - Frankly, there's so little reason to go see him, and by the time you do, you've killed all of his market, so it doesn't make sense to me that he could get mods on demand.
Sydney - She's a merc, not a merchant.
Tulip - Limited access to trade supply chains.
Generic scavengers/merchants - Too much of a hassle to handle.

Questions:
Pop-up when each mod is available/have the mod delivered to you by courier or by script?
I do not plan to make the mods delivered to you by courier, or script, or to have the game give you a message saying a mod has been delivered. You must return to the original vendor and use the grab key on them again. All of the scripting is based on the event of pressing grab in front of a merchant, and the delivery times are stored on inventory references in dedicated containers. I have no intention of attempting to track every possible delivery commission and have them sent to you or provide message popups, it would be a pain in the ass.
Can I get ___ unique/unique-ish mod like FIDO with this system?
Yes. There is no prohibition for using this system to acquire late game or unique/uniqueish mods like FIDO or such. If you can find the weapon, you can commission delivery of any mods it uses via the appropriate vendor.
Make the mod available for a single time purchase indefinitely regardless of vendor inventory reset/available for infinite purchase?
I don't intend to prohibit commissioned mods from disappearing on the vendor's inventory resetting. It would be a bit of a hassle, and I like the idea that they just put it on the shelf based on your delivery request, and if you neglect to get it for too long once acquired, someone else will probably "buy" it.
Will I miss out on the delivery if I take too long to return to the merchant?
The items will not be added to the vendor's stock until you prompt it by pressing Grab while targeting the merchant again - there is no chance of losing the commissioned mod under any circumstances, until you prompt the system to move the mod to the vendor's inventory.
Have Barter/discounts/Charisma/story outcomes affect the commission price?
I don't plan to. I'm currently happy with those being affected by the post-delivery purchase.
More delivery slots?
Nah.
Dialog option to prompt the delivery system?
I have no desire to mess around with dialog.
Faction money for commission cost?
I don't really want to bother.

Permissions:
Do whatever.

Support:
If you'd like to support my modding work or say thanks, feel free to donate via the Nexus or here at Ko-Fi.