If you are looking for a well designed and inexpensive remote for your PC, then look no further. Check out the streamzap remote.

Of course, I can’t speak for the Windows drivers and/or software, but the Linux support is wonderful. Recompile lirc with the streamzap support and you are all set. There are plenty of MythTV config files and .lircrc files to be found. However, if you are stuck, leave a comment with your real email address and I will get them to you ASAP.