While a plugin would be ideal, have you considered just using a script and a DIV block inserted into the header.php file of your theme? I use a jquery banner script – http://www.mclelun.com/blog/2010/01/jquery-rotating-banner/ – on one site. It just cycles through four banners, each with links. BuddyPress already has jQuery in place, so I think it should work if you follow the guidance on the page re. the banner. Yes, it’s a quick and dirty solution – with no clever tracking within the site, but it is at least a solution!
