If Apple indeed increases the size of the next iPhone’s display to 4 inches, I do not expect them to increase the physical size of the device itself. There is plenty of room on the current iPhone for the rumored 4-inch display — just shrink the non-display areas on the front face. On the iPad, the thick bezel area surrounding the display serves an essential purpose — it gives you a place to rest your thumbs while holding the device. The non-display “forehead” and “chin” on the front face of the iPhone serve no such practical purpose. All Apple needs is enough room for a home button at the bottom, and the speaker, camera, and proximity sensor at the top.
This is exactly what I have been telling people. Apple should be able to create a bigger screen without a bigger device.