I never actually believed Apple will make a complete new design for the 5. The 4 is way to succesfull with the premium feel of the glass, on the front and back, it's which separates the iPhone from it's competitors. All that iPadish design rumours for the back is just nonsense. The most logical thing for Apple to do was to perfectionize the 4 by slimming it down and giving tt a bigger screensize and making the antenna round the phone seemlees with the glass front and back for a better grip.
The fake iPhone by the Chinese is a good clue on how the real one will look like, the fake is clearly more chunky and looks cheaper but that is also the same case with the fake 4 models.
Therefor I actually do believe this is the new iPhone 5. Eventhough it looks like a slimmed down 4 but hey that's the most logical thing to do for Apple. This combined with the great resemblances with the fake chinese iPhone...I think Macrumors has the scoop for the iPhone 5. Oh yeah and about the screensize, looking at the chinese 5 cases the 5 supposed to be wider and therefor the screensize will be bigger without being it an edge to edge display. This maybe will happen when the make the screen bigger when building the iPhone 6.