No it looks the Power Pilot is not your only option. It may be the case that any standard magnetic bicycle speedometer can be made to work with the Lemond Revolution trainer. The Lemond revolution does have an embebed magnetic sensor in it's flywheel. So all that is needed is a way to position and attach a speedometer sensor, so that it can read the magnet embedded in the flywheel.

My Experiment which resulted in a working and realistic reading from my low cost speedometer setup consisting of the following ingredients:
Bell Platinum Series, Bell Wireless Cyclocomputer
Four zip ties
Sturdy heavy gauge steel wire
Electrical tape (to wrap around the wire to protect the bicycles paint)
Pliers to bend and shape the wire such that the sensor lines up properly with the magnet.