Apple has retained the display sizes of most of its mobile products. The full-fledged iPad still have a 9.7 inch display. It was only with the iPhone 5 that Apple increased the display size of its smartphone by .5 of an inch, the first iPhone that came out in 2007 and up to the iPhone 4S the company stuck with a 3.5 inch display. However, Apple is taking a beating in certain niches from Samsung, which is putting bigger and bigger screens on its devices each quarter, take the Galaxy Mega 6.3 for instance. Rumor has it that Apple too is testing devices with larger displays, an iPhone and iPad to be precise.
The report comes from Wall Street Journal, which cites sources from Apple's suppliers in South East Asia. The sources claim that Apple is testing an iPad with a display that measures 13 inches diagonally, significantly larger than its current iPad that has a 9.7 inch display. For the iPhone, it is said that the company might go above 5 inches in the future, quite possibly with the iPhone 6, which has long been rumored to have a bigger display than its predecessors.
Obviously it can't be said for sure exactly when these devices will hit the market. For all we know, they can be prototypes that Apple is merely testing and currently has no intention of releasing. The fact remains though, Samsung is taking a huge chunk of its market just because it is not restricting itself to specific display sizes. Furthermore, the Korean company has created a big phablet niche for itself with its Galaxy Note devices, Apple doesn't have any offering in that lucrative market.
New Apple products are expected to be unveiled this September. The company is reportedly going to unveil two iPhones, the iPhone 5S and the low cost iPhone, and quite possibly the Retina iPad mini as well as another variant of the iPad mini that does not have the Retina display.