We do have a bit (very small amount) of history re: Russia and the U.S. in the fallout universe. It comes primarily from one of the premade player characters in the early series. Russia wasn't annexed, at least not at the time the great war started. They talked a big game about the U.S. being their enemy, but relations were actually much more cordial than one would expect, and far better than say during our cold war. I can make this mod, but some help would really speed things along (as I'm working on several projects). If you don't have modding skills, that's OK too, because ideas for quest lines are just as important, if not more so, than technical skills. If you want this mod to be made, contribute what you can, even if it's just brainstorming ideas. Right now it's in it's preparatory phase and if I don't feel like it has legs (especially in regard to the story line) it may be put on a back burner and forgotten. I haven't played Fallout 1 or 2 in a very long time, and tactics really focused on the BoS and hardly had any prewar context to it, I was referring to Fallout 3's DLC with the Chinese as current lore. However since the lore isn't really set in stone, which I think is really why I love Fallout to begin with, you could work in anything really.