BuddyPress.org

Just as a follow up to this, here is the relvant urls:

http://willnorris.com/2008/10/wordpress-openid-v3

https://wordpress.org/extend/plugins/openid/

According to Will, it’s already working in WPMU so we’ll have to look and how to make this work in BP. I’ve got a client interested in this, so hopefully I might report back in the near future.