Marvin the Robot
Marvin the Robot is a RC controlled lawn mower. still in beta.
what is done right now is motors are mounted to a simply 2x4 frame. after I get a metal frame welded up I'll mount my lawn mower to it and add the wheelchair motors, batteries and controller box.
http://www.flickr.com/photos/38834202@N06/sets/72157620729703133/ ( here is my flickr set with mouse over notes)