When putting the ToM together it struck me that the timing belts looks a lot like tank treads when flipped inside out. I think small robots are fun so I decided to try making a chassis based on some 140XL timing belts.
This is the parts that I ordered for eBay;
[Edit] The 300RPM motors where no good as they had to little torque. So go for these;
I added a small project description over at LMR http://letsmakerobots.com/node/27218
The parts are symmetrical so print 2 each of the sides and end parts.
Two timing belt pulleys that have to be taped and set with a M3 set screw.
The rollers has a ball bearing inside and the two halves have to be glued together. Ps. these are not symmetrical so bare that in mind when you mount them.
The holes in the base plate and end pieces have to be taped for M4 bolts.