Hmm. Could be useful as a starting point. It's written for a 2.4.x kernel so you'll need to make some changes.
It's still only a mass storage device though so if you want to mount the music partition under Windows then you'll need an ext2 fs driver.
I would have a go at rewriting it but I'm really busy for the next week or so. If nobody else volunteers then I'll have a look after that.

- Trevor