Fake research. More garbage to spin around and get attention. Apple is not doing a phone past 5" and I would even consider a 5" iphone to be nearly impossible for them do since Jony Ivy is heavily against formfactors or sizes that gets too far away from being useful and purposeful.
A 5" iphone would easily be too big for the typical iphone buyer to manage even with a very thin bezel. The largest I think they would try for is a 4.3 - 4.7" sweet spot.
I actually thought the Samsung Galaxy S2 was the perfect size.
Although I agree with you that it is very unlikely that Apple would release an iPhone over 5" I disagree that a larger phone "gets too far away from being useful and purposeful" People talk about the importance of one handed operation but how many iPhone owners actually use two hands as much if not more as one handed operation when you are doing tasks that requires more than a quick glance. Years ago during the number of portrait only mode apps outnumbered ones capable of doing both or landscape only but that has now shifted and you can use far more apps in landscape mode now as well. Many games are landscape only, texting for me at least is far faster with two hands or should I say 2 thumbs, looking at websites is easier to read in landscape, pretty much anything I do on my iPhone that takes me longer than 5 seconds to look at the screen I tend to switch to landscape mode. I suspect I am far from alone and for anyone already viewing landscape mode a great deal they will definitely appreciate a larger display.