Instapaper developer Marco Arment argues that the idea of a 5-inch screen iPhone has its own logic and created a mockup showing how it might look on a device.
If the Retina iPhone has screen with a resolution of 326 pixels per inch, this is not the case with the Retina iPad which is limited to a resolution of 264 pixels per inch.
Based on this observation, Marco Arment calculated that Apple could offer an iPhone with a screen of 4.94 inches with a resolution of 264 pixels.
This screen of 4.94 inches would display a definition of 1136 x 640 pixels, the same as the iPhone 5, and then developers wouldn’t have to do anything to support this new iOS device.
In his mockup, Arment placed such a device between the Samsung Galaxy S 3 and the Samsung Galaxy Note 2.