OK, I got that grey mouseman today from Tigergirect. It's PS/2 and serial. The only problem is it has the shortest cord I've seen on a mouse for some reason. As if to be plugged into a keyboard. You'll need an extention cord.
Dam...I just ordered mine on saturday. Let me know if you find any extension cords. That must be how the price is so low....the just snip'd the rest of the chord to save money!! hahah.