apparently their will be a delay in the shipment of iPHONE 5 due to Touch Panel Issues . Source http://www.mactrast.com/2011/09/iphone-5-shipments-delayed-due-to-touch-panel-issues/ if it is a 4S then i doubt they would have trouble producing the same screen they have been producing for more than year , wont you think ? this must mean the new iphone will have different dimensions for the screen , possible meaning a new design.
http://www.youtube.com/watch?v=fX7uKuvUItI&feature=player_embedded The case preview video found by realeric was enough for me to be VERY confident of a larger screen. Now I have no doubt at all that it will happen