I was thinking about a simple bipolar stepper driver, what if you got a simple microstepping driver chip that drives a small stepper directly, say the Allegro A3967, which has nice features, but limited to 750 mA of motor current, and added a little circuit on the output to drive a push-pull type stage.
Lets say 4 of IRF 540's.
I didn't get a price on the chip but lets say it costs $10.00 and the FET's cost about $15.00-$20.00, thats a $30.00 bipolar stepper driver, with 100V 20 amp capability...
There would have to be some kind of connection for the current sensing, but little else. The resistors are just to give some kind of balancing load, and would be the same value, and rated to suit the additional FET gate currents
I'm sure there is some reason it cannot be done, but I can't see it, so who is going to burst this bubble ??? I have put a pic of the schematic to extract the positive and negative signals to fire the push-pull stage, don't laugh I did it in a bit of a hurry.
I bet it is Al or Kreutz.