interesting? you can use sunrise.php to support multiple domains with one user table, but I’m not sure how site_url() (BuddyPress) would react to it. Search for wpmuguru. He’s really good with configuring multiple domains/databases on multi-user. It would be interesting to test and with enough custom code, you could make almost anything happen
ps.. you should mark the topic as resolved since this really isn’t a direct support question.