A guy over on traxxas was doing this, I have a link to 1 of his projects but he took all the PICS OFF !!! it had like 8 wheels and he cut diff cases in 1/2 and just glued them together and threw the pinion on the other side and something else, but he is the king of adding tons of wheels he did a few different ones im sure would come up with a search.
http://monster.traxxas.com/showthrea...=space+shuttle