Couple things to keep in mind - first, the iPad pic was obviously real, and was leaked before the iPad got announced. It's in some strange frame (possibly to hide the actual look of the device), but it's still obviously the iPad. So that is a 100% legit picture. There are two iPhones in the picture, one full one sitting on the iPad, one on the bare edge of the picture. The edges of those devices look exactly like the edges on this thing. So it's pretty safe to say this thing is legit as well.
Second, Apple is big on secrecy. When the iPhone was being developed, before it was officially shown off, there were two separate teams working on it, hardware and software (and sub teams within those groups). The hardware guys got the barest in placeholder software, just enough to test the hardware functionality (we've actually seen this, when a prototype iPhone went up for sale on eBay - all the icons/buttons were blue rectangles with white text, and were mainly test functions). The software guys got generic boxes full of electronics. Both groups got various designs, to hide the final design and to help point at who leaked any information.
So this could very well be a prototype that's not the final design, or at least an earlier design.