There is a rumor going around that the new iPhone (which I think will just be called iPhone and not the iPhone 5) will have a 4" display. They speculate the device will be as wide as the 4/4S but with a taller screen making the device longer and capable of handling an extra row of icons. For some reason, that didn’t make sense to me even thought the math for determining the resolution density seems plausible from a non-engineer like myself.
It wasn’t the math that felt odd. It was the fact that Apple would change the form factor that, despite a few tweaks here and there, has basically remained the same since 2007. When Apple felt a high resolution was necessary, they didn’t make a bigger device as their rivals have done. They changed the screen and force it to conform to the device. That’s what makes me think Apple will keep the general size of the device the same but use as much of the device as a screen as possible.
Perhaps, they’ll change the home button as has been rumored before. It might be oval; it might be a capacitive touch button like the screen. And perhaps, they’ll move the earpiece and front camera further towards the top of the device. But the mock ups of an iPhone with a 4" screen assume that the buttons and microphone take up roughly the same size and I think that’s a mistake.
I’m using my Field Notes steno book as a ruler here (not mathmatical in any way) but the diagonal dimensions of the iPhone 4 is roughly six inches. I certainly wonder if you can squeeze a 4" screen with an elongated hight without changing the size of the device from the current form factor. I think it’s possible if Apple makes other design decisions and turns the phone into mostly screen.
It’s a total guess on my part but I don’t see any reason why Apple has to change the size of the device to fit a .5" larger screen when the real estate is already there. Apple has been known to push the limits of both design and manufacturing. I don’t see what they can’t do that again and reorganize the insides of the phone to conform to their screen. What else is that nanoSIM card for?