Interesting project!
I wonder if using a 418mhz IR-RF module that you could then use URC's MRF250/MRF300/MRF350 RF-IR extenders?
I presently own a URC mx-950, which has both IR and RF transmitters in the remote.
I know that it transmits at 418mhz to URCs MRF RF-IR extenders.
But I don't own a RF-IR entender, but I am going to be hiding some of my components shortly, so I'll need RF.

I also am interested in using these PDAs as remotes(I just ordered a HP rx3715).
But I want to use RF on them instead of the IR or WiFi for compnent control, and also be able to use the mx-950, using RF, with one RF-IR entender unit for both remotes.