After talking with my dad, he said that he had a toy usb controlled robot, called a "bo bot". It used a basic stamp controller, and had warnings on it saying to only use digital servo's for required operation. He said that knew the digital servo's were exactly the same, but tested them at that time with an old futaba receiver and found no differance in form, or function between digital and regular servo's. He used some old servo's he found in a am receiver box he got from his dad, shortly aftter he died.
At the time I remember it functioning with an old mxpc controller he had when they were fairly new.
My dad is big into pic controllers, has and adrunio, and plays around with his reprap a lot. He is getting ready to build his second one. The thing I find funny, he has no idea how to size electric motors. I think you would get along well with him.