The Wall Street Journal is reporting that Apple is planning to ramp up production of the next iPhone--predicted to be the iPhone 5S--sometime this quarter. If the WSJ's sources prove accurate, this could mean Apple is aiming for a summer launch of the next iPhone. September is still within the summer time frame, so we could see the device being announced roughly one year after the iPhone 5 was first announced.
The sources say that Apple is still working with partners in Asia on a cheaper iPhone model. This model is expected to feature a 4-inch screen and a different body than the high-end model. It's possible the case could come in a variety of colors like the iPod touch.