The theory is easy to understand: perform John GruberÂs Mini-predicting math backwards. The iPad Mini uses iPhone 3GS-density screens at iPad resolution. What if an iPhone Plus used Retina iPad screens with iPhone 5 resolution, keeping the rest of the design sized like an iPhone 5?
Its 640 x 1136, 264 DPI screen would measure 4.94Â diagonally, and it would look roughly like this next to an iPhone 5:
(via MacRumors)
Cheers,
Scott.