try brecoflex if you decide to go with a tread drive train they have some custom pulleys made for their timing belt. Basically you'd want to run your axle(s) to one of these cutoms pulleys and wrap the tread to the other points where pulleys would free wheel and just keep the tread in place.
http://www.brecoflex.com It seems pretty simple if you look through their catalog. Good Luck!