A long time ago I saw some controllers that were similar in an old' school DIP-package auto-insertion machine that I had to nurse along from time to time. But I was just the night-shift operator of the machine and would read the tech manuals for it between cycles. I got to know that machine better than the maintenance crew did. In fact they unofficially called on me for light-duty repairs. (It was always wearing out a few segments of ribbon cable by flexing them to death.)
It sounds like you have the basis for a really killer toy CNC project.
I posted some files that allow people with an Arduino and a free copy of LinuxCNC to make there very own CNC machines. If your interested it can be found at http://emc2arduino.wordpress.com/