I do suppose the IR extender route would be less work, but I always found navigating menus with the remote to be more awkward than using the front panel with its D-pad-esque button arrangement. I also tend to drop or lose the remote in my car. I could always mount it semi-permanently, but I think I'm going to at least play around with the input panel idea, even if it just turns out to be an educational project rather than anything practical.

Yeah, the other good thing about the Arduino CAN board that I didn't mention is that it's pretty cheap. I did run into that PCAN-USB module on the RPi forums, and once I saw how much it cost, I realized Arduino was the ticket for now.