I guess you could then mount the phone on the back and then fit that to a large format camera via an adapter and have full movements one your iPhone! I'd better get me an iPhone and then...
The problem is really some phone cameras are going silly now the latest Nokia 41mp Nokia Lumia 1020 - Best Camera Phone 2013 with 41 MP - Nokia - UK
So getting mp on the sensor isnt a problem so why havnt Canon or Nikon gone that mad on a full frame sensor (the closest being the D800) Quality I remember reading that some thought the sensor to the D800 was overpopulated