Volunteer Lab Rat has an interesting project allowing you to build a 3D Scanner out of some common parts.

“The following blueprint shows an exploded view of the vital components of the rotating table. I use an R/C servo to rotate the table. It would be easier to construct a table using a steppermotor, but I had an R/C servo on the shelf.
The servo cannot rotate a full 360 degrees, so I use a oneway bearing to be able to rotate the table 180 degrees (which is the limit of the servo), and then move the servo back to it’s inital position. Now I can rotate the table another 180 degrees. A decent grade oneway bearing works without any slack at all. I will not go into details with construct the circuitry, and it’s allmost at cheap to buy a servoboard from www.picobotics.com as it is to build one yourself.”