PC Perspective saw a notebook with a built-in projector at Asus's Computex booth:
Taking up a large portion of the top of the display was a small "mini projector" integrated to the chassis. This creates a large portion of what most would called "wasted space" on the bezel above the LCD display but obviously a machine like this would have an incredibly niche audience that would be willing to ignore such facts.
The projector itself rotates and swivels in order to tuck in well for closing the notebook lid. I wasn't able to really see how well the projector worked - the room it was in was pretty bright.