Images have leaked today from China of what appear to be the iPhone 6. There is just no way to tell though if they are real or fake.
"It is entirely unclear whether the device in the images is a legitimate iPhone 6 part or a fake. Early prototypes of the iPhone 5s and the iPhone 5c exhibited a blank rear shell while the iPhone 6 shell in the picture clearly shows FCC text that is generally added to the phone at a later date."
I expect Apple to release two new sizes of the iPhone this year so even if these are fake (which I think they are) they give us a good idea of what a larger iPhone could look like.
You can see more of the photos at Sonny Dickson.