BuddyPress.org

A quick google reveals several bulk-import scripts and plugins for WordPress/MU. Have a look at http://www.dagondesign.com/articles/import-users-plugin-for-wordpress/.

Regarding bulk import of xprofile data: Manjor Kumar had done some BuddyPress-specific import plugins for a very early version, but I can’t vouch for if they still work:

https://wordpress.org/extend/plugins/bulk-import-members-users/

and

https://wordpress.org/extend/plugins/user-import-for-buddypress-all-fields/