I can't believe how difficult this is to find. I need a simple MP3 player that I can embed in posts that supports the use of XML playlists. I have looked at half-a-dozen players and none of them do this. They are all set up to play video lists from YouTube or Vimeo, but not of them seem to be a simple MP3 player. The closest I've been able to get was "mp3-player-plugin-for-wordpress" but that has really weird playlist support and require you to copy your MP3 files directly to the plug-in folder.