New reports have surfaced that the iPhone 5, now slated to be shipped in fall 2012, will have a aluminum back, joined to the glass front by a plastic/rubberized bezel.
Earlier reports stated that shipment would start summer 2012, with an aluminum back and a slightly larger screen (4").
Lots of time left till either supposed shipment date. Lots of rumors to come.
Source: 9 to 5 Mac