Either every single outlandish rumour surrounding Apple's upcoming [iPhone 5]( is real, or someone has been reading the blogs and sending around "case leaks" again. We'll bet on the latter until there's real physical proof of the former.
If you're into this sort of thing, though, MobileFun is claiming two sources on these cases, which show off a bigger screen, sound controls on the opposite side of the iPhone, and no home button, just a large gesture area.
Steve Jobs originally intended for the iPhone to be buttonless, but found he couldn’t quite get away with it. It looks like he’s some way closer to that goal with the iPhone 5; the physical home screen button has been replaced with a touch-sensitive ovaloid area which takes up the middle half of the bottom border. This area might be used for unique multi-touch gestures, given its increased size.
Again, take with the largest grain of salt you can ingest without crystallizing.