I spent almost 3months looking on ebay - never saw an RCM CRT.5 there, there's been a few here, but they go quickly. I just got my RCM CRT.5 kit. Mike's made some changes to make side to side balance better by offsetting the drive train slightly and going to a batt tray to let you balance fwd and back weight distribution better.

The prob with a rtr based conversion is power - if you put a decent bl motor in one, you spend a lot of time walking over it to flip it over and put it back on its wheels.