BuddyPress.org

Thanks for all the reading material …

WP 3.0-Beta2-14508 + BP 1.2.3 (all freshly installed on a clean server)

… with steps 1 and 2 only from @Phlux0r‘s post above: https://buddypress.org/community/groups/miscellaneous/forum/topic/buddypress-and-wordpress-30/?topic_page=2&num=15#post-50233
… and replacing the bp-core-avatars.php code completely with this from trac: https://trac.buddypress.org/browser/branches/1.2/bp-core/bp-core-avatars.php?rev=2957

All seems to be working quite well.

Thanks!