I have recently been working on a 3D stereoscopic Camera rig, Here are some details!
I used 2 Canon Powershot A480 cameras to build this rig, Mounted side-by-side in order to take pictures at the same time. Used together with software to process the images, it can be used to create cross-view 3D images (side by side, right image on the left side, cross your eyes to view), or can be used to create anaglyph images (red/cyan offset images that require special glasses), or several other kinds of stereograms. In order to synchronize the cameras, they are running CHDK with remote shutter support turned on. I am using two 3V lithium coin cell batteries in series, a pushbutton, and a dual USB port pulled from the front of an old computer case to trigger the remote shutter.
The left camera is mounted upside down to provide access to both USB ports, and to bring the lenses closer together, The mounting system includes a center pivot point to adjust the focal point of the image. The cameras were mounted via 0.25 inch screws cut to length to fit the tripod mount on the cameras. The software I wrote automatically rotates the left image before drawing it to the final, combined image.