Yes, there are others in the collaborative creation space. Indaba's currently leading, and I know and love the guys behind it.
Really? That's pretty cool, I used to be a developer at merge.fm, would love to talk to the Indaba guys if you could drop an intro. My site's: http://roshfu.com if you want to make sure I'm legit first :)
Contacted you over Twitter to keep this page as uncluttered as possible ;)