MacRumors has obtained a new photo which compares what is believed to be the back of the new iPhone.  The new iPhone back is in a matte finish that we have seen before.  Other than that, there is no more information.  We can kind of get an idea of the new iPhone design from the bezel and now the matte back. Not much difference in design, but some changes nonetheless.  The back would certainly be much less prone to scratching.