This close to launch, be it Summer or Fall, I can guarantee you that Apple is not still developing the next iPhone, it's form factor and general design has been long since decided. At worst, they are still doing minor internal tweaks, and at best they are in the procurement stage and prepping for full scale manufacturing.
Apple has probably known what the next iPhone would look like prior to even releasing the iPhone 4S.
Apple has probably known what the next iPhone would look like prior to even releasing the iPhone 4S.