Kernel Bob 
I broke down my old Rostock MAX 3D printer. I saved the frame rails, belts, and stepper motors, among other parts. I upgraded my Prusa MK3 to MK4S. I saved the linear rails, bearings, belts, and stepper motors, among other parts. I've always wanted to make a camera motion platform, and now I have a lot of rails, belts, bearings, and stepper motors...
The MK3 controller board is only an ATmega, but it has the nice Trinamic stepper drivers.
Dustin