Hmm yeah we have a BuddyPress & bbPress Forum ourselves and I was actually wondering about how Disqus would work on a BuddyPress site. It was decided a long time ago that we would not add any "connect-like" logins: Disqus, facebook, etc. to our Forum to avoid unnecessary complications. The slight convenience factor is just not enough to justify the headaches of doing api connections just for a simple thing like creating a user account. ;)
Glad to hear everything is working. Thanks.