Scrolling avatars on header?

I've been playing around with Drupal this week, building a site. It's a great piece of software, so far I'm very impressed :)

What I'm looking for is a module, or advice, on how to scroll through random user avatars on the header. You can see what I mean in this image, with the yellow and green rectangles each being a different avatar. The black bars on the side will have the site name.

http://www.chainsawfilms.com/images/headexample.jpg

I'm using the newfangled theme.

I'd like to be to take at random a selection of user avatars, say 20 to 30 at a time and have them continually horizontally scroll in the middle of my header. Whenever the cursor is placed over it, the scrolling stops and you can click on an avatar, taking you to that user's page. Ideally, every time the site loads, it builds a new random selection of users, but if necessary I can rebuild the list every day or two.

Thanks in advance!