According to sources, the new iPhone chassis would be used on the rumoured ‘budget’ version of the iPhone and could be sourced from an unnamed US electronic manufacturing provider and the casing could change from the much recognised Aluminium and glass of the iPhone 4/4s to plastic. The transparent aspect comes from a separate rumour whereby a new design could see the metal sub-structure of the device visible through some sort of special casing.
The rumor in the supply chain is that the inexpensive iPhone chassis supplier will reportedly be a US-based electronic manufacturing service (EMS) provider.
Sources claim that such material is currently going through validation testing, but we have heard that the next iPhone, whether that be the iPhone 5s or iPhone 6, has already been spotted being testing in Cupertino, suggesting that such a radical design change would not be only going through validation testing. If true, it is likely we will not see this until a generation after the next version of the iPhone, unless the rumours of the ‘budget’ iPhone are indeed true.
It seems unlikely that the transparent casing holds any strength as a rumour, with Apple spending significant time investigating light-leakage in the iPhone camera. Any transparent casing on the rear of the device would no doubt affect the performance of the camera. Consequently, I find it difficult to believe this rumour is something Apple will consider, even if it will yield a lower manufacturing cost for a budget iPhone.