BuddyPress.org

here is your code
http://buddydev.com/http//buddydev.com/public-download/unified-search.zip
Put the code of functions.php in your functions.php and move the single-search.php and search-loop.php to your theme.
You may check more details on my site here.
http://buddydev.com/buddypress/creating-the-sitewide-globalunified-search-page-for-your-buddypress-theme/

@mods: hope I am not doing anything wrong, but if you feel it inappropriate linking my own site, please feel free to edit this post

Edit: Sorry, the initial download link was incorrect