I was just reading a thread about the Kona Sutra. There was some controversy about the disc brakes on a tourer, and the problems they pose for mounting a rear rack.
I got to thinking - since the front brakes do most of the braking (read Sheldon's article on braking if you haven't), why not put a disc on the front and canti's or V-brakes in the back? My old motorcycle has a disc in front and a drum in back.
Just a thought. Any reactions?