As we can see from the photo is supposedly an iPhone 5 with 4-inch LCD panel is essentially larger in height but not width. In this manner, the overall size would remain contained and there were too many usability issues.
The late Steve Jobs, former CEO and co-founder of Cupertino, was always opposed to the large screens, aware that they can be comfortable for web browsing or viewing of multimedia content, but impractical if we use the phone with one hand.
Now that Tim Cook took the reins of the U.S., things could change. The official announcement of the product should take place after the summer, but it is not impossible that some clue about it before getting to the event at WWDC in June 2012.

