Cool, I'll definitely look into these types of algorithms. Do you have exposure to these? I'm still a 3rd year undergrad and my maths isn't strong enough yet to grok some of the crazier algorithms.
Actually I was curious enough about this novel use (and I happen to be interested in music myself, who isn't) I saw your post and thought about replicating it and emailing you results. I'd be more than happy to work with you on any non-commercial stuff. (An email address which works for me is on my HN profile, could you send me a note? Even if nothing else it doesn't make sense for all of us to spider/scrape the same datasets over and over...)