Here is a list of mod ideas that do exist for Fallout 3, but haven't been ported or modified to work with New Vegas. These ARE lore-friendly, & would make sense to be in the Mojave Wasteland:
- Iguanas: A mod from Fallout 3 by Sesom that introduces a really cool Iguana creature along with amazing features to go with it. It would make sense to have Iguanas in the Mojave, considering that Iguana Bits & Iguana Sticks do exist in New Vegas.
- Cryo Weapons: A mod from Fallout 3 by Captain-Ultima that introduces & improves upon cut cryo weapons. There is a similar mod for New Vegas by Clanf (Awesome mod, BTW), but the Fallout 3 one greatly improves the weapons, rather than just re-adding them.
- Ties that Bind: This isn't lore friendly itself, but if someone made a companion that is essentially a close relative of the courier (Wife, Husband, Brother, Sister, Son, Daughter, & so on...), it would be an amazing mod, provided it was done right.
- Fallout Slavery Overhaul: Another Fallout 3 mod by Sesom, this one overhauls slavery in Fallout 3. It would be a great addition to a Legion playthrough. I've only played as a bad guy ONCE, & that was as an evil dictator of "Independent" Vegas, but a mod like this could get someone to enjoy being a legion character much more.
I might add on to this with fresh ideas later on if this page gets some attention. I hope you agree on the suggestions, & enjoy you stay in New Vegas!