I got the VEX 6-Channel Remote Controller from Ebay for $40. The non-vex receiver was 9 bucks.
I also got the Jaycar motors for the feet (from New Zealand), the Sabertooth 2x25 speed controller and the wheels from Banebots.com. I hope to use the smaller wheels to drive the larger wheels since I don't have a source for fabricating the elusive aluminum drive hub.
I started building a wooden interior for the main feet where the motors and wheels will be mounted. My success with the wood/styrene combination for the dome ring inspired me to try a wood structure for the feet. That, and the fact that wood is much easier to cut. I am still nursing my tennis elbow and that 1/8" styrene is a bear to cut.
Now hopefully a trip to Douglas Hardware tomorrow for screws and bolts will allow me to start the process of getting R2 motivated!