For the past few months, it's been possible to purchase what appear to be unreleased iPhone parts from sketchy parts vendors in China. Japanese newspaper Nikkei took some of the aluminum shells to its sources in Apple's(s appl) supply chain, and while it found the shells aren't perfectly convincing, they do provide a rough idea about what to expect from the next version of the iPhone.
According to the Nikkei report, which is written in Japanese and was interpreted with the help of Google Translate, the currently available shells have a low build quality -- the home button doesn't fit perfectly, there are rough edges, and there are unpolished burr marks. So it's unlikely that these shells are actual Apple parts. But Nikkei's sources say the final iPhone 6 will look very close to the available mockups: for instance, they say the Apple logo will in fact be cut out, which matches what we've seen from other leaked parts. The final iPhone will also be similarly thin with an iPod touch-like design, but will likely feature a different antenna design on the back than the mockups currently show.
Apple is expected to launch two new iPhones this fall, one with a 4.7-inch screen and one with a 5.5-inch screen.