Diemai, have you looked at Aussie lures like Halco (Poltergeist, Rellik Doc) and Predatek (Boomerangs, Woomera) offerings? I think the Aussies are wild over the bananaish lures but they usually render it with a plastic lip. Some slight modifications in the basic banana shape in those lures addresses the roll over issues you mentioned. But I agree the amount of curvature in the lure dictates a lot of the lure's action. For buoyancy issues, try playing with wedged shape body cross sections too, this will help a lot in addressing the needed stability.
Hazmal's lures are to me in the banana category too (oops, better put a disclaimer in here, I'm referring to the lure shape not the man
) I think Pete will know a lot more Aussie lures that are banana.
