I have been asked this same question when visiting our local hobby shop and I have given it some serious thought. A 4 channel radio would never work, but a 6 channel radio might. What if you use the throttle channel for the variable pitch and use an upper channel to control the motor speed? Then you would have an "idle up" mode that brings up the RPMs and a more normal feel to forward and reverse. If you have a knob that you can use for throttle, you can vary your RPMs... if not, you should be able to use a two or three position switch to give you at least low and high RPMs.