This USB mouse can be transformed into the shape of the Trypticon character and it will look great together with the Optimus Prime Transformers 4-Port USB Hub.
The 3-button 800 dpi Transforming Laser Mouse is compatible with Win98/Me/2000/XP/Vista and Mac. The product is available from the Bigbadtoystore.com website for $59.99. (Update: Link removed because the page is gone.)
Via a bunch of great blogs: