9to5Mac reports that Apple is currently testing two prototypes of the iPhone5 that offer a taller screen while still keeping the existing 640px width.

According to the report, the two prototypes will have a display of 1136px, up from the current 960px and giving an increase in the diagonal size of the display from 3.5 inches to 3.95 inches.

These prototype phones are floating around Apple HQ in thick, locked shells in order to disguise the exterior design to “undisclosed” employees. We know of two next-generation iPhones in testing with a larger display: the iPhone 5,1 and iPhone 5,2. These phones are in the PreEVT stage of development and are codenamed N41AP (5,1) and N42AP (5,2). Because Apple reserves certain models for internal-only usage (such as the N96 phone we previously reported on), we’re not sure which of the two devices will make its way into the world later this year.

Rumours of a larger screen iPhone5 have been coming more and more frequently as leaks come from parts companies alleging to be supplying parts for the next iPhone.

Image via Niilo Autio