I made a pretty inexpensive primer counter for my Pro 2000 with the help of an electronics whiz. It has a micro-controller that was programed the way I wanted it.
The Press Monitor products are pretty pricy, but if you don't mind that, they just may be what you are looking for.
Carl's Electronic Kits sells this up/down micro-controller controlled kit ($23.00) that could be powered by an old phone power supply, and the counting input could be a strategically placed micro-switch similarly to what I did with the primer counter above. (you do need a soldering iron)