There's a few different lines in the MacBook family for the example the MacBook, MacBook Air, MacBook Pro, and pro with retina. Same with iPods there are few different varieties there..and now the iPad with regular and mini.
Do you think we will see iPhone pro? Or iPhone air or iPhone mini? Would it be a smart idea for apple to release options like this?
Multiple iPhones have been discussed before, but usually about different screen sizes. What you have mentioned is a similar concept. IMO having different screen sizes would make more sense to us the users since there has been so much divide and discussion about which screen size is the best.
As you have pointed out, Apple has multiple selections for most of their other products. When it comes to the iPhone it seems they stubbornly stay with only one updated product. Their other choices aren't really much of a choice. They are the previous year's products at a lower cost and rather than a new product line that's being updated with better specs like the iPad mini.
I am very curious why Apple chooses to stay with only one sized iPhone when having two would ease many of the bitter complaints and discussions about different sizes. People have given several different theories as to why not, but Apple is company and if there is enough demand it would surprise me if they didn't make both. I do realize that unlike most companies, Apple does tend to do what they think is best even if it's not what others think is best, but they have also given into user's demands if there is enough of it.
The iPad mini is a good example. Apple didn't seem to really want to make a smaller iPad, but with the popularity of smaller tablets from other manufacturers they decided to make two iPad sizes, so why are they still unwilling to make two iPhones sizes when it's such a hotly debated topic among users? IMO two sizes is all they need because I think it will satisfy the majority of users.