david, it was my understanding from your post that your building an Alt-Az goto system which tracks in Alt-Az. This system would still need a Wedge and then your program would need to be converted to use your Alt-Az motors as RA-Dec. This is similar to Mel Bartel's system and the Meade Autostar Fork system. It will be intresting to see what you come up with and the total cost. Good luck.
Tom Hole
http://www.tomhole.com/EQ%20Platform.htm
has built a EQ Platform using a Hurst Bipolar Stepper motor.
The Hurst 300:1 0.025 degree per step motor used on EQ platforms in the USA is available online for $15 US. See link bellow (I hope its ok to post this link)
http://www.electronicsurplus.com/com...oduct_id=71092
Hurst Specs are here for this series of motors.
http://www.electrosales.com/hurst/lsg35_geared.htm
I wonder if these are used in any old equipment, we could rip them out of these. But $15 US is not too bad.
And the controller is for $29 US see link.
http://electronickits.com/kit/complete/motor/ck1404.htm