DIY Motorized Zoom for your DSLR

Clems Video production is a one-man-show. He has to switch back and forth between being the subject and the cameraman. Constantly moving around the workshop for every single little correction is very tedious. Why not upgrade any common DSLR with a remotely controlled Zoom/Focus? Commercially available motorized zooms and focus pulling devices are very expensive, so Clem develops his own cheap and flexible solution and finds out if is it worth building this sort of camera equipment yourself. What kind of expensive equipment should he try to recreate next? http://bit.ly/335ahRI