This [Dwight Shrute]-esque project will let you try out your taxidermy skills. Apparently you can acquire a ‘wetware’ mouse fresh or frozen from pet stores. We just need to wait until fall when our pantry is visited by the less-domesticated variety.
A travel-sized optical mouse acts as the replacement guts. Some creative dremeling brings the plastic housing down to a more acceptable shape. The furry bits need to be processed using the mouse taxidermy guide before they are fit over the electronics. What you end up with is a creepy peripheral that nobody wants to use.