Hello Amraduk,
I just came across this thread and I had the same idea with my Revox reel to reel machine.
A repair service for Revox tape maschines here in Germany is selling such a counter based on a PIC 16F628 - unfortunatley quite expensive (119 euros).
The rotations of the capstan motor are detected by two IR-phototransistors and the value of the 4digit counter is stored in the eeprom of the PIC when the power is switched off (using a large cap, as described here in ajs_derby's posting).
http://www.revox-bandmaschine.com/zaehler_77.htm
To use this counter instead of the mechanical one you have to enlarge the window on the front panel, what I wouldn't do. But I found very tiny 0.2 inch LED displays (what might interest you too) here:
http://www.kingbright.com/product_ma...20050525051040
What about your counter? Is it finished and working yet?
Best regards,
Bernd