The production of those displays has apparently been poised to start next month, which makes sense if Apple would want to put it all together towards the end of the summer.
The WSJ report did not pinpoint a screen size, but the sources have mentioned it will be no less than 4". Now we've analyzed ad nauseaum how today's phones can have larger screens and still be as compact, light and durable as the ones with smaller screens of yesterday, so that's what might be going on here with Apple's 2012 iPhone.
Considering that Apple is very adamant that people still reach everywhere on the screen with their thumb during one-handed operation, instead of having to use two palms, a 4-incher would be the sweet spot.
Its other selling points are said to be thin metal chassis and LTE connectivity, as well as all the goodies that will come with iOS 6, like the rumored homebrew Maps software Apple is allegedly prepping for its gadgets.