David, thats exactly what I would do too.

To drive a stepper motor in full steps is simple, though if the motor is loaded you need to develop some means of accelerating the speed so that it doesn't break step.

To run in half step slightly complicates matters, but running microstepped is a lot harder, here you need to add DACs to regulate the current in both windings.

Matt, is your article going to cover ustepping, and if it isn't do you want to see my article on it !

Steve