I think if it were me, I'd go with a stick radio, and use a pair of outrunners to power the rear wheels. Might be a little more expensive, but I'm sure you could find a cheap alternative for the controllers. That way you wouldn't have to deal with the turning issue. If you decide to do a standard setup, a 1/4 scale servo would probably be the only thing that could handle it. Or perhaps you could use 4 outrunners and have it 4wd.
I don't remember exactly how well it worked, but I remember ChC did some experimenting with two motors on one controller, and I think once he got the motors timed together just right, it was fine, but since they would be powering there own wheels, timing them together wouldn't be a big deal. That way you can have the left and right independent of each other and that could be your steering, kinda like how the Tyco Rebound was.
That thing was INDESTRUCTIBLE. 2 story roof? No problem. lmao