Re: 'Cash For Kills' concept
You could make a "mercenary" gamemode, or create a mercenary-themed campaign game. Instead of being a very wealthy/important figure with their brain preserved, you're just an opportunist looking for work. Instead of a brain, you have a logistics computer in your base- or you can be a disembodied brain too, just the brain of a mercenary figure who won't die!
Instead of "clones", you have "lackeys", and only you gain monies from kills. Other factions (Green and Red brains) don't.
Multiplayer would be sick, with 1 red brain player, 1 green brain player, 1 black brain player (Criminal syndicates or mercenaries)...
... and 1 purple hive-mind (Indigenous carnivores). No, wait, now I'm just getting carried away...