I don't think any ones done somthing this expansive, but it may already be done. Someone with alot much time on his hands should sanbox the entire wasteland region and create hundreds of NPC's to roam and survive like the PC. But i mean true surviving. When they need to sleep they will find the safest place around and sleep.When they need to eat they will eat. They need to keep their individual supplies up by hunting and trading, and they will manage their weapons and armor. They could travel in groups or alone, and they can be recruited as followers if wanted by the PC. I think this would take alot of work and scripting knowledge, but it would be very worth it. I have also heard of a mod called Wasteland Wanderers, but i don't think its the same. This mod would be great if it were combined with somthing like RTS, but so the NPC's could intelegently create their own temporary/permanent settlements. Even better would be if NPC's that travel were from different factions, and could go into combat against each other. There obviously problems with the idea, but it could be tackeld by a veteran modder.