Argh, it's funny, but I almost posted this when I saw it... while enjoying the 'Persecution Complex' of thinking "Amigans" should've been able to do it first and better (hint: cameras are getting almost cheap enough to stick one on the back of the laptop and not disrupt your field of view, though a bit of head-tracking and/or tilt sensing would be required to get the perspective exactly right)*...
Meanwhile, of course, Englebart beat everyone to the whole 'whatever you're working on genlocked over video' thing, and the Mac camp have been having a bit of fun with that, too --
see here.*At which point it might just be cheaper to use a clear LCD with a one-way backing, though that makes backlighting an issue for a panel of much width, which is why we rarely see it. Not to mention that they used to hide the driver electronics behind them, but that's been changing recently.