ooh, It is possible that your controller might work, but not the drives. I use turbocnc 4.01 right now as my controller on my old p166 laptop. I use Gecko drives wich are hooked up to the step and direction pins of the parallel port output wich outputs the pulses to the motors. They are top of the line stepper drives 10microsteps per step, that means I get 2,000 steps out of one revolution vs 200. I plan on running about 80vdc through these motors when I get around to it. This will give me rapid movements over 120ipm
Im guessing your drives use half stepping or possibly full stepping with fine thread leadscrews.
The handwheel addition will probably be nice, the only thing is that when using ballscrews you can push your table around by hand when there are no motors attached, for simple stuff it would be a problem, like moving the stuff around, but you would definately have to have the Z axis motor powered up to do any milling.
I just got done milling part of my motor mount for my new 1.5hp dc motor for my spindle
http://www.cnczone.com/gallery/showphoto.php/photo/722
Jon