"Explay has developed the world's smallest projector, a revolutionary nano-projector engine small enough to fit inside your pocket or be embedded in your mobile device, allowing you to truly enjoy the big picture wherever you are." The company says the screen size will range from 7" to 30". A working device has been demoed last May.
Do you know if there are any projectors that you can hang vertically so that it projects up or down the wall? If not (and I suspect not), is it impossible for reasons that have to do with how optics work? Very curious.
Korean Company Shows Prototype Of Pocket-Size Projector
Siemens Shows Off Phone With Projector
Future: Virtual (Not Only) Keyboard
Future: Personal Video Projectors