Re: BuddyPress on WP (Not the WP mu ?)
Unfortunately not, at least right now.
What I consider the main reason for this, among the others, is that WPMU has a specific plugin directory devoted to “instant on” plugins, and BuddyPress relies on that specific ability within WPMU to activate itself and to load up all of the necessary files and functions.
You could, however, install WPMU and BuddyPress together, but then turn off the ability for users to make their own blogs. This will essentially make it operate like a WordPress.org install on the outside, with MU/BP’s sweet creamy insides. 
