You mean one of these? Yeah, Microsoft could make some good money bringing these back. I know I'd worry less about mine biting the dust.

http://cgi.ebay.com/New-SEALED-RETAIL-PACKAGE-Microsoft-Opti...

http://cgi.ebay.com/SEALED-BULK-RETAIL-PACKAGE-Microsoft-Opt...

http://cgi.ebay.com/Microsoft-TrackBall-Optical-Mouse-PS-2-U...