A 4.7" iPhone 6 with the internals of the 5.5" iPhone 6. I am currently using a 5 inch LG G2. It is a tad too big. 4.7" seems to be the sweet spot, for me at least. But 5.5" will definitely give Apple more room for battery, a better display, 2gb ram? While I can live with a lower spec on those, I'd like the camera to be the same. Because if the the 5.5" has a better camera, I will reluctantly go for the 5.5".