Those people are showing off, Yoc, but someone could easily do this cheaper and easier, with a little bit more setup time and with a loss of stability (in my house, that would be fine, since I'm often moving things around, rather than creating "stations" for tasks). In the end, you have a v-shaped block to set the book, two heavy transparent objects (glass or plastic, preferably attached in the same v-shape), and the two cameras hung perpendicular to the page. Oh, and the bright overhead lamp.
If you didn't want to go to the trouble of opening up the cameras to synchronize them, you could just press the two buttons from the perch between page turns.
The real issue, I think, is that cheap digital cameras are actually even less useful than they claim. Due to the construction and--especially--the lenses, you start getting blurring artifacts at anything over six megapixels, so you're not really getting the effective resolution you think you are. (Or at least, that was still the case a couple years back. I'm not a camera guy--I believe my sole camera is "VGA resolution" and cost me ten bucks, and seldom used--so that may have changed recently.)
