BuddyPress doesn’t touch user authentication. Whatever works with WP/WPMU will work with BuddyPress. I know http://bit.ly/17TEbD works. Someone like Boone Gorges might be able to comment if they use a LDAP plugin/which one.
As far as I can tell LDAP is not just about user authentication, but also about exchanging or synchronizing data with other directories or member management systems. So it includes issues like getting data out of xprofile etc.
Thanks for the WPMU-LDAP plugin! I’ll try that one first.
