My CNC winder needs 2 stepper motor drivers: the original Egg-bot has an integrated EiBotBoard which can easily control 2 stepper motors (plus lots of servos). But in initial tests I was unable to get the EiBotBoard from my Egg-Bot to spin the motors fast enough, and I also wanted to use limit switches and wire-break and emergency stop switches. I'm sure the EiBotBoard could accomplish all this, but I would need to reprogram its firmware (an interesting project but I'd like to finish this one first!).
Instead of using the EiBotBoard I've opted to used two of Brian Schmaltz's easydriver stepper drivers, connected to a PC parallel port via a CNC4PC C-10 breakout board. The whole thing will controlled by the opensource machine control software EMC2.
For fun I connected the EiBotBoard and Egg-Bot pen holder to the machine and tried plotting on a cylinder from Inkscape using the Egg-Bot extension. If you made the linear traverse unit tiltable you could also plot on cones.