At the Consumer Electronics Show, Hitachi is demo'ing a product called Starboard that is a multi-touch interface at a very large scale. You can use it to control a regular PC, and they've also got some custom apps for it. One of those is shown in the video.
What's interesting is that this is a projected interface, so it's untethered from the need to have a touch-sensitive LCD. This allows it to scale very large relatively inexpensively. They were also showing a wall-size version.
The projector in both cases was a very short throw Hitachi model that could produce an amazingly good image from an extreme angle. For the one in the video, the projector lens was maybe a foot above the surface, perched top-center of the image. Yet the image was completely distortion free and perfectly rectangular and about 4 feet across. Same thing with the one on the wall, which was an even more extreme example.