Interesting; is it only disc brakes that require specialized mounts, or can those be rigged up too?

I think keeping the rear brakes as a rim might be useful as well, as others have mentioned these aren't the most powerful brakes (don't know if wheel size has a factor in that). Together I figure they're more than enough, and it isn't like I'm racing. Other than roller brakes, what then would be better? I only have experience with rim brakes and haven't had anyone tell me about anything else in practice (just theory).

M.