There's a thought. Would I return the iPad Mini and buy the larger iPad, if Apple finally and rightly released a larger iPhone? Probably not. The phone is used for calls, texting, photos and short reading. The larger iPhone would simply make looking at photos and reading easier. However it still wouldn't be as good as the 7.9" Mini display for larger articles and books. Also I find the gestures of the iPad more natural and I believe this alone increases my productivity when researching. The reason I want the larger iPhone, around 5-5.5", is because it is my go-to mobile device when in work or walking around and so I would like to do more on it. So, make reading easier, make looking at photos easier, make typing and formatting easier and make watching videos more comfortable.
I initially thought the larger iPhone would replace the iPad altogether but after more consideration I still think the Mini has a place in my "technology bag" - particularly after thinking about my researching productivity.