1) BP for caps is bad idea. Major gangs with their exploiting ability would get advantage over solo players or small factions. There is a lot of something / caps possibilities.
Idea of BP, or any other random based feature has positive effect of clearing differences between two previous groups. Of course, that statisticaly great faction has better change to find BPs, but quality? VSB, although not biggest faction, although only part of us hunted BPs, founded first Combat Armor BP.
2) Vaults, Mariposa, but even a Necropolis.. good place to find technical BPs. Limitations? PKs, local radioation of great values (=Fallout of Nevada concept), poison, more critters. BPs in Junktown? Yes, why not. It is open for half of a day, it limites the players (they have to wait outside, or inside). Add BPs to non talking NPCs, so you can steal them.
But focus this mechanism into existing ficed locations, even guarded. There were too many features rejected because they would unpopulate cities (fixed locations), but during implementing new features they forgot it. It looks like devs are amateurs that realy dont have vision to create working MMO project. They work hard (seriously), but they dont know how (seriously). This MMO project great advantage (Fallout universe) is almost depleted without any proper replacement. So sad.