Unwire.hk (via MacRumors) shows what they indicate may be screen protectors for the new iPhone 5. Interestingly, the screen protectors here show a wide home button (above) and when compared to the current iPhone 4, show a wider screen area (below).

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If the current aspect ratio is preserved, the new size would indicate that the screen extended further toward the top and bottom of the device.

Another closeup image, below: