My better half wanted something like this for work - only thing he could find at the time was the playstation-run site
SkiveSuite - he downloaded System Skive - just a flash animation-thingy that runs, you can alt-tab out of it, so I don't know how useful it would be - it fooled a few people where he works though
I believe there's a screenshot on that site though - IIRC it's not a very big download either