Rivaling gangs is difficult. Because technically they all share the same race. So if you shoot boron pirates you also lose rep with split pirates. Which is a pitty but it's not possible to do it different.
Nomadic pirates are cool but i don't think npcs could really give you that feeling. Ramming their great command base-ship into the next asteroid does not really add to the atmosphere
Regarding nomadic piracy for the player - in XTC there are the mobile stations which could even give you production capability but are still moveable. And the crew mostly is not picky about the food ^^ e.g. i mostly pillaged and robbed in terran and boron terrain mainly and wherever i was, i could just feed them with the stuff i "found" there. And the ships are basically free... for a pirate *g*
2.0 brings new features, and pirates are not forgotten
happy looting mate