Interested in building your own custom remote for your XBMC? Make shows off a guide to make your own using a cheap Bluetooth module and a custom case.
The build here uses a Bluefruit EZ-Key, a bit of soldering, and (an admittedly pretty ugly) 3D printed case. The process itself is pretty easy to do, and once you're done you'll have a compact Bluetooth remote you can use to control your home theatre PC. It should be easy enough to modify the case to suit your style.