Well, we're about 12 hours away from seeing the thing for real, away from the speculation and leaks, but these two photos popped up just a few minutes ago. We don't know if it's real, but it certainly could be.
So here's what we can see: A tablet in the general form of an iPhone, including the trademark home button, looking like it's encased in some kind of S&M leather case with snaps. It's running what seems to be a larger, scaled version of the iPhone's mobile Safari browser, possibly with tabs. In the upper left, it looks like it says "No Service", which would be referencing 3G (also a ha! moment for AT&T, if it uses AT&T) as well as a Wi-Fi logo. Very little else can be ascertained, including the most important pieces of the puzzle, the software and keyboard.
Is it real? It's the most likely suspect in my mind, not least because it only popped up the night before the event - Apple's security is so tight that this is the most leakable time. But it is, right now, unconfirmed.