On my site I have vanilla (other than themes) versions of: - Latest WPmu - Latest BuddyPress - Latest BBpress Now for some reason, they aren't integrating cookie wise. The logins should be integrated, if you login to either then you're signed in for both; and if you logout of one you logout of both. It's probably something simple missed along the way. Let me know if you can get this working and your price.
hit me up with your url and a better explanation of your problem and maybe i can help you out! i run a bp/wpmu site