The thickness of both devices would appear to be 7mm. That would allow both models to be thinner than the 7.6mm Apple iPhone 5s. Making the iPhone phablet so thin might make for a great looking handset, but it is making it hard for Apple to find a supplier for the kind of thin battery cell that the model requires.
While there have been various rumors as to when the iPhone phablet will launch, with some speculation that the phone won't see the light of day until next year, the latest rumor is that the 5.5 inch version of Apple's smartphone will be released in September.
Cases leak for the 4.7 inch Apple iPhone 6 and the 5.5 inch Apple iPhone 6s
source: NWE via RedmondPie