The Padzilla is an iPad "case" that makes its screen 150 inches diagonal, which is, well, much bigger than it normally is.
Really, this is a lot like touch surfaces like Microsoft's Surface Table. You simply plug your iPad into it, and it'll mirror what you see and share its multitouch properties. It's a custom job, so you can have it made in sizes ranging from 70 inches to the grandaddy 150 inches. Just why you'd need a 150-inch iPad is beyond me, but hey, if you've got a reason, now you've got a way. Oh, and by the way, the 70-incher will set you back between $30,000 and $40,000, so if you want the 150-inch model you'd better save your pennies.
See a video of the 70-incher below.