One of the complaints we have about MythTV is that the music player is very unintuitive.  Have a brief read of the thread http://mythtv.org/pipermail/mythtv-dev/2005-July/038011.html where some discussion is underway about a replacement that is a frontend/backend system, using the DAAP protocol (http://daap.sourceforge.net/) that ITunes uses.
 
http://cvs.mythtv.org/trac/browser/trunk/mfd - backend
http://cvs.mythtv.org/trac/browser/trunk/mfe - frontend
 
When I get home I'm very interested in having a look at this and it might pay to look at helping this project rather than doing anything with MythMusic. 
 
Craig