Its a nice idea, but I think you'll find the FCC rules on standard RC equipement preclude its permanent installation (there are only a very few channels). I don't think I've heard of an off-the shelf solution, but how about this:
A multi channel button-push transmitter (there are chipsets for 4 button remote controls that can drive IR or RF transmitters with a pulse-code stream, and matched receivers that output logic signals at receiving end.
Microcontroller with motor-controller uses one of the lines as a speed increment signal, another as a speed decrement signal - so you have a two-button up-down speed control remote?
For instance I've got a main-socket remote control (RF) that uses an SC2262 to drive a 343MHz OOK transmitter. I think the corresponding demodulator chip is the SC2272.