I've been trying to figure out a way to control the iPad with a large multi-touch display. After scouring the internet, I've read many times that this is cannot be done, however here's a company that's doing it (without jailbreak): Padzilla 70 Inch iPad/iPhone Case. Does anyone know how this is possible?

Thanks all!

The link does say "contact us for more details". That would be the obvious place to ask.

It appears, from what I can tell, as though this is a full peripheral "case", which is relaying capacitive touch directly to the iPad screen via a closed front cover as well as taking a video out from the dock connector port. A clever way round the issue, but only practical for this precise implementation (i.e. demonstrating on a large external touch screen) since it puts the physical iPad device completely out of commission in its own right.

The other downside is of course that the screen is part of the "case". That ain't going to be cheap!