Mark Chance
Boingy! Boingy!
I've just started to fiddle around with Mouse Guard and think that game could handle a situation like this very well.
Sounds intriguing. If you'd like, you could post your Mouseguard experiences in this delightful thread.
Regarding basic conflict types, don't forget the ever-popular Man vs. Himself, in which the story's protagonist faces his own limitations and inner demons. Not sure how'd you build an adventure around this sort of conflict, but it could certainly be worked in as subplot material.