Where to buy custom gearboxes for WCD's

I recently read a thread about West Coast Drive, and someone mentioned that it'd be better to use a custom gearbox for a West Coast Drive, but my team has no experience with making custom gearboxes, and not enough time in the current build season time to make gearboxes and a robot. We don't meet as often during the off season, and rarely during school brakes. Does anybody know where we can find gearboxes that work for West Coast Drive, or how to mod the given ones to a West Coast Drive?

Thanks!

P.S. It'a not that we don't want to build our own gearboxes, but we don't have the time/know-how/parts to build them. We are planning on getting some workshops in for the coming year, since all of our mechanics graduated, and they were the only ones who ever built custom gearboxes.