A couple weightless mods offered separately. (Food/Alcohol/Chems, Crafting Items). I couldn't find this on the Nexus already (or at least not as I wanted them), so I made one for myself and figured I'd share. Scroll down to see all mod descriptions.

Let me know if I've missed anything. And feel free to make requests. 

Weightless Food, Alcohol, & Chems
Description:
This file changes ingestibles to be weightless (including those that are marked as Quest items). I couldn't find this on the Nexus already, so I made it for myself and thought I'd share.

Requirements:
Just the base game. No DLCs required.

What WASN'T changed:
Hides, food-type items marked as misc (ie: Yeast, Deathclaw Eggs, Flour, etc.), food-type items used for Big Guns, items that are already weightless (ie: Stimpacks, Med-X, etc.)

What WAS changed:
Absinthe, Ant Egg, Ant Meat, Ant Nectar, Ant Queen Pheromones, Fresh Apple, Atomic Cocktail
Beer, Bighorner Meat, Bighorner Steak, Blamco Mac & Cheese, Bleak Venom, Bloatfly Meat, Bloatfly Slider, Blood Pack, Brahmin Meat, Brahmin Steak, Broc Flower, Bubblegum, Buffalo Gourd Seed, Brahmin Wellington, Banana Yucca Fruit, Barrel Cactus Fruit,
Caravan Lunch, Fresh Carrot, Cave Fungus, Cazador Egg, Sweetroll, Cook-Cook's Fiend Stew, Coyote Meat, Coyote Steak, Coyote Tobacco Chew,
Dandy Boy Apples, Deathclaw Eggs, Desert Salad, Dog Meat, Dog Steak, Doctor's Bag,
Fancy Lady Snacks, Fire Ant Egg, Fire Ant Fricassee, Fire Ant Meat, Fire Ant Nectar,
Gecko Kabob, Giant Rat Meat, Gecko Meat, Gecko Steak, Grilled Mantis, Gum Drops,
Human Flesh, Human Remains, Honey Mesquite Pod, Healing Powder,
Iguana Bits, Iguana on a Stick, InstaMash, Irradiated Beer, Irradiated Dandy Boy Apples, Irradiated Fancy Lads, Irradiated InstaMash, Irradiated Crunchy Mutfruit, Irradiated Mutfruit, Irradiated Banana Yucca, Irradiated Barrel Cactus, Irradiated Gecko Meat, Irradiated Potato, Irradiated Potato Crisps, Irradiated Salisbury Steak, Irradiated Scotch, Irradiated Sunset Sarsaparilla, Irradiated Sugar Bombs, Irradiated Irradiated Water, Irradiated Whiskey, Irradiated YumYum D. Eggs,
Jalapeno Pepper, Junk Food, Jake Juice,
Lakelurk Eggs, Lakelurk Meat,
Mireluck Meat, Hatchling Mireluck Meat, Soft Mireluck Meat, Mole Rat Meat, Mole Rat Stew, Mole Rat Wonder Meat, Moonshine, Mother Darkness, Miss Quantum Pie, Mushroom Cloud, Crunchy Mutfruit, Mutfruit, Medical Supplies, Maize,
Nevada Agave Fruit, Nightstalker Tail, Noodles, Ice Cold Nuka-Cola, Nuka-Cola Quantum, Nuka-Cola, Nuka-Cola Quartz, Nuka-Cola Victory, NukaLurk Meat,
Pinyon Nuts, Pinto Bean Pod, Pork N' Beans, Fresh Potato, Potato Crisps, Prickly Pear Fruit,
Radroach Meat, Ruby's Casserole, Rat Meat, Rum & Nuka,
Scorpion Poison, Scorpion Poison Grease, Spore Plant Pods Fresh Pear, Salisbury Steak, Scotch, Silver Sting, Crispy Squirrel Bits, Squirrel on a Stick, Sunset Sarsaparilla, Stealth Boy, Strange Meat, Strange Meat Pie, Sugar Bombs, Imitation Strange Meat Pie,
Trail Mix, Tremble,
Vodka,
Weapon Repair Kit, Drugged Wine, Wasteland Omelet, Purified Water, Dirty Water, Whiskey, Dixon's Whiskey, White Horsenettle, Wine,
Xander Root,
Yao Guai Meat, YumYum Deviled Eggs

Weightless Crafting Items
Description:
This file changes crafting items to be weightless. Food items listed above are not included. Crafting items mostly taken from: http://fallout.wikia.com/wiki/Fallout:_New_Vegas_crafting (Though I also added Teddy Bears (non unique) to this list because, well, I like to collect them.)

Requirements:
Dead Money, Honest Hearts, Old World Blues, Lonesome Road, Gun Runners Arsenal

What WASN'T changed:
Foods listed above, items that were already weightless.

What WAS changed:
Abraxo Cleaner,
Bent Tin Can, Box of Detergent Blank Book, Blank Magazine, Butter Knife,
Coffee Pot, Coffee Mug, Conductor,
Deathclaw Egg, Duct Tape,
Egg Timer, Empty Soda Bottle, Empty Sunset Sarsparilla Bottle, Empty Syringe,
Fission Battery, Flour, Fork, Forceps,
Fire Gecko Hide, Golden Gecko Hide, Gecko Hide, Green Gecko Hide, Glass Pitcher, 
Hot Plate,
Jar of Cloud Residue,
Large Burned Book, Large Ruined Book, Large Scorched Book, Large Destroyed Book, Lead, Lunchbox, Leather Belt,
Medical Brace, Metal Cooking Pan, Metal Cooking Pot, Metal Spoon, 
Pilot Light, Pot, Pre-War Book,
Scrap Electronics, Sensor Module, Scrap Metal, Scalpel, Small Burned Book, Small Ruined Book, Small Scorched Book, Small Destroyed Book, Surgical Tubing,
Tanned Fire Gecko Hide, Tanned Gecko Hide, Tanned Golden Gecko Hide, Tanned Green Gecko Hide, Tin Plate, Teddy Bear, Tin Can, Turpentine,
Wonderglue, Wrench,
Yeast

New in Weightless Crafting 1.1:
Bark Scorpion Poison Gland, Black Coffee, Cazador Poison Gland, Deathclaw Hand, Fiery Purgative, Healing Powder, Healing poultice, Radscorpion Poison Gland

New in Weightless Crafting 1.2:
Empty Whiskey Bottle

New in Weightless Crafting 1.3:
Empty Nuka-Cola Bottle, Large Whiskey Bottle, Legion Denarius, Nightstalker Blood, Nightstalker Egg

Weightless Crafting - No DLCs
Description:
This file changes crafting items to be weightless. Food items listed above are not included. Crafting items mostly taken from: http://fallout.wikia.com/wiki/Fallout:_New_Vegas_crafting

Requirements:
Just the base game. No DLCs required.

What WASN'T changed:
Foods listed in Weightless Food, Alcohol & Chems; items that were already weightless.

What WAS changed:
Abraxo Cleaner, Bark Scorpion Poison Gland, Box of Detergent, Cazador Poison Gland, Duct Tape, Egg Timer, Empty Syringe, Fire Gecko Hide, Fission Battery, Forceps, Gecko Hide, Glass Pitcher, Golden Gecko Hide, Leather Belt, Lunchbox, Medical Brace, Nightstalker Blood, Nightstalker Egg, Radscorpion Poison Gland, Scalpel, Scrap Electronics, Scrap Metal, Sensor Module, Surgical Tubing, Tin Can, Turpentine, Wonderglue, Wrench, Yeast

New in Weightless Crafting - noDLC 1.2:
Empty Soda Bottle, Legion Denarius, Pilot Light