I dunno i think it might actually be fairly easy to make a br rogue like, I might start hacking one this weekend...
as a start:
-randomize weapons/characters
-characters have randomized loyalties to each at varying strengths which control allegiances. As time passes stress increases and if stress > loyalty the character turns.
-beyond that just create a large jungle/city landscape and implement the dead zones.
Magnum pretty much hit the nail on the head with my thoughts on it. I'm not sure how well the NPC's would interact without the main focus of the game being that, but being careful and outlasting the maybe 20-30 who pose a threat would be an interesting challenge indeed.