Electronic Z-Crank

After using my new Z-stage ( http://www.thingiverse.com/thing:10478 ) for a while, I found one annoying problem: there is no easy way to adjust the position manually. With the original Cupcake stage, you just pull on the timing belt. Or install a crank on one of the threaded rods. With 10478, the only way is to turn the threaded rod directly, getting oily fingers in the process.

This thing is an auxiliary stepper controller, which can be inserted between the printer's motherboard and stepper