Ok, messing about, I found a basic web server written in AutoIT3. I gutted that completely, and gave it the ability to control windows media player using just data passed in a URL:
http://127.0.0.1/index.htm?next=1
would advance to the next track, for example.
Then I coded a window Inventory.MediaPlayer that puts the right URLs in the HTML window and presses the GO button. It's kludgy as heck and there's no feedback into the game of what the playlist looks like or what song is currently playing and there could never be a realtime update of current song.
It might be possible to put the data of a playlist in HTML format and display it in the browser page, although I'm not sure "realistic" and "possible" should be confused in this case. It was a very basic web server and now it's nearly lobotimized. Plus, either it doesn't like the EQ2 viewer or the EQ2 viewer doesn't like it. I'm having trouble getting even simple text to show in the browser window atm.
Anyhow, if someone is really interested, I can post the .au3 code and/or the mediaplayer.xml window. I'm not sure I consider the whole thing useful enough to pursue further. I was just interested in if it was possible at all.