http://www.deltang.co.uk/ has all you would need to do it cheaply. Tiny receivers, simple transmitters, just enough features. I'm in the process of converting a Weaver GG1 to this system. Eliminate the third rail, use two-rail GarGraves track, eliminate all the bother of track wiring, voltage drops, dirt, phasing, etc.
I'm using the TX22 (has momentum, reversing, directional lighting) and an RX102-1 receiver. Costs about $100 and I can use the transmitter for 12 locos at the same time.
So, that's the rebuttal to "It can't be done" "It can't be done cheaply" "No one has a complete railroad-oriented system" "There's no room for the receivers" etc.
