Heh, I've actually thrown this idea around, I just got frustrated trying to line the camera up properly and I've got a fairly jittery hand. Now so long as you never move the laptops, you're set.
heh. I once wondered about that as a way of cloaking vehicles. Lots of tiny cameras and lcd screens in a pattern all over, with each LCD displaying a live feed of the other side.
No, that wouldn't complete the effect, since the webcam would be sizable and there'd be a difference between the image it captured and what you should be seeing through the laptop. What's included, or rather excluded, in the frame and the perspective would be out of sync.