The prototype shows the elongated screen, smaller dock connector and the headphone jack on the bottom that have all been rumoured to feature on Apple's new baby.
Tech news site GSMIsreal were the first to spot the device, which was apparently shown off by a case manufacturer at the show.
The manufacturer, who wasn't identified, has already developed cases based on the rumoured design.
Top of the Pops
Meanwhile, pictures have appeared on the internet showing a Chinese popstar with his hands on a "working" version of the iPhone 5.
Jimmy Lin, a Taiwanese-born Chinese popstar has posted a picture of himself using the device on microblogging site Weibo.
According to Lin, the 4-inch screen and 19-pin dock connector are features of the new handset while the casing is the same aluminium alloy found on the iPad.
Rumours continue to swirl about when Apple will unveil the new iPhone, but many believe we could see it as early as September 12 - with handsets arriving in the shops as little as nine days later.