I think a Tomcat web app would be a little overkill for what I'm trying to do.
I don't want to handle actual streaming of the music, just create a new folder system that gets automatically updated when I update my iTunes library. Anyway, I managed to get an initial version working last night. I've attached a SVN patch if anyone is interested in using it. Just apply it to your working copy, then put "useitunes=true" in your PMS.conf file. Also, if you don't keep your iTunes folder in <user.home>/Music/iTunes, it doesn't find your itunes library folder automatically and you'll have to show it where it is by setting "ituneslibrarypath=/path/to/itunes/folder".
Most of the work went into parsing the iTunes library xml file, as it is a bit of an odd format. There are a lot of improvements to be made still. For instance, put the configuration in the GUI instead of by properties only. Also, lazily generate the whole virtual folder structure as needed to reduce memory usage. My library of about 30 playlists and 3000 tracks takes up an extra 25mb of RAM when the server loads up due to having the whole structure in place. I may get to improving this some more later this week.
Ok, well the forum won't let me attach .patch or .txt to this post. So I'm not sure how to get the file up here.