I like your idea very much ...
What about extending OpenMoco for taking panorama pics (gigapixel and spheres)?
How do you control the steppers? Any additional hardware like EasyDiver ?
Could you add some pictures to illustrate OpenMoco?
I DIYed a two axis-stepper-driven-robot combining an Arduino, two stepper drivers, two small steppers, two gearboxes, a 20x4 LCD and a Wii Nunchuck to take pics with a DSLR-cam. My gearboxes are imho too big and I would like to replace them with wormdrives, but could not find some reasonable priced ones.