Wanting to try again that old AJAX interface I got awhile back (when I was running OS2007), I gave it another go (now with OS2008 "Diablo"). It worked, sort of. It's unpolished and buggy. So I set out to find a more recent version. After some digging, I came upon the author's site where he hosts the now-named iBrowse:
http://www.liquidicelabs.com/xbmc/installAJAX.php

jj, did you ever come across this? If not, I think you'll love it. It even has working volume buttons.

Here's a screenshot of it using Album Art. The interface resembles iTunes':



Dan