At this point everyone knows that there will be a 4.7" and 5.5" iPhone 6 being released later in the year. One question I had is will Apple launch a 4" iPhone 6?
I am going to say no for a few reasons.
1) When Apple introduced the iPhone 5 it was only introduced in one size - 4".
2) If Apple were to introduce a 4" iPhone 6, it would cause confusion as the new iPhone, 5c, and 5s all would be the same size.
3) An additional iPhone 6 size introduces supply chain and inventory management issues. Three different phones in three different colors is 50% more combinations than two different phones in three different colors.
One argument in favor of producing a new 4" iPhone is ease of use. Many people want a phablet but a majority of the people are fine with a smaller phone. There doesn't seem to be any reason for Apple to alienate it's core user base.
One way Apple can get around that problem of ease of use is to reduce the bezel's at the top and bottom of the phone and stretch the screen to use more of the space on the left and right side. By just making the phone a bit taller and wider there would be no reason to introduce a 4" iPhone 6.
I do think the 5s will take over and become the new 5s line in color. Will the current 5c line survive? That would leave the 4S as the cheapest phone and a big gap in features and price to the 5s. An easy way to have the current 5c line survive is to keep the same colors and introduce the current 5s with different colors.
Then Apple would have the 4s, current 5c, current 5s, and two new 6 phones to compete at a variety of price and feature points. They haven't had 4 different phones on sale before, except for a few occasions when the 4 was also on sale with the 4s, 5c and 5s.
Disclosure: The author is long AAPL, GTAT, PXLW.
Additional disclosure: The author also writes covered calls on the above from time to time when market conditions are favorable.