Perceptive Pixel demonstrated a multitouch screen that uses a series of cameras to track as many points as is placed on the screen. You can have multiple people interacting with multiple fingers at the same time. It also features gestured based movements like on an iPhone to make items larger or smaller and there is acceleration/deceleration of images being moved around on the screen.
They come in 27″, 55″ and 100″ sizes with the 55″ model costing around $60,000.
It is currently in use by such media companies as CNN. Here’s an example of the technology being used across multiple monitors: