This L6470 chip from ST has SPI interface to control stepper motors. It accepts high level commands, like step x count left and ramp down! It has built in analog and digital inputs to aid in making stepper controller and can control medium size motors, perfect fro 3D printer or laser cutter. It even has a built in regulator so you do not need 3.3V, just give it ht motor voltage and it is happy!
Of course this chip is perfect for NETMF as it handles all the stepping automatically from SPI commands.
Let us know what you think and if this interests you please.
Any volunteers to write the drivers? We will get you a free board of course to play with.