That's my prediction. We're only about two months away from the annual iPhone announcement date, based on the cycle in recent years, and there have been many parts leaks for the 4.7" model building over the past couple of weeks, but we haven't seen anything from the supposed 5.5" model. Apparently, one analyst is now saying that the 5.5" model is "delayed" and may not get released until November or 2015. That is such a classic analyst line about Apple. I think the Apple TV set is delayed too. This is one of the benefits of Apple's secretive ways. They didn't promise a 5.5" iPhone. It had not release date set, so you can't delay something that was never officially expected to happen. Under-promise and over-deliver seems to be one of Apple's motto's and it has served them relatively well.
I was never really convinced we would see the 5.5" model this year. I still believe we are likely to get a new 4.7" model and another year with a 4" model. Maybe the 4" model will only be this year's equivalent of the iPhone 5C (6C?), but I don't expect them to jump straight into two new sizes. But, in the next 5 minutes there could be a new part leak that totally blows away prediction, so I guess we'll see.