Well, I would think that the 4011 would be paired quite well with a vehicle like an upright delta trike, that would be my ideal application for such a motor. Balance desire though, thats understandable, i've just finished putting together my Xtracycle - and while I don't have a battery right now, put the motor on to test out the balance. If that motor was on the rear, the thing would be *ungodly* weighted towards the rear end, especially loaded with gear! The front motor keeps it a little more even.

Personally, i'll be switching to a frame mounted motor utilizing a P5 Cargo sometime down the road, but for now the 408 on the front end provides good balance.

Personally, it seems like a 4011@72v is overdoing it. My 408@48 goes up those grades with some pedal input quite well, but it all depends on how much input you want to be doing personally I suppose!