Is your request for fans to be purchased or existing fans. If it is for future purchases, X10 relays and dimmers can be driven by IR. For example, look at smarthome.com. They have theirs own and other lines of x10 dimmers that can be used to provide varaible speed control for celing fans. Their shopping assistant at
[Link: smarthome.com]specifically mentions this capability. Once installed an X10 device numbered IR543 can be used to convert IR signals to X10 signals.
I have two fans that are controlled using this method and they work well.