I used SageTV for awhile and they had something like that. Basically in one of the setup screens you had an option for remote control setup. You would press a button on your remote and the command would show up in a window, then there would be a list of all possible things you could want to assign that button to. If you wanted button press '9' to mean '1' or FF button to rewind you could tell it do that.. just a stupid example.. you could assign any key press on the remote to do whatever you wanted it to in SageTV.
Not stupid at all... sounds like a very simple and easy to use way to configure /setup a remote. I agree something like this is needed in LinuxMCE. Mantis this and set the ball rolling ;-)