I liked the angle you were going for in the opening post. As for the bad guy/other bounty hunter I was thinking that he would be a bit of a funny guy who reveled (at least a little bit) in the female bounty hunter's incompetence lol. Like he would string her along to make her think that she'll catch him but then get away at the last second (because he's terrible people) to force her to think about her mistakes more clearly. Of course he has his own reasons for being a bounty hunter and why he is so blase to the entire thing that we can get into later if we roleplay (to kind of mix up the morality of things). His funny persona sort of falls apart when she gets in trouble though, as he feels some sort of duty to turn her into an (at least) adequate hunter.

This is just off the top of my head though, so feel free to pick through it. As for plot ideas, I don't have anything solid down yet, but what about something...political perhaps? Like setting it back in the Cold War era or something? I'm not sure what time period you would want this in so *shrugs*