Since the Apple iPhone 6 will be a cottage industry unto itself, the case manufacturers who get their product out first have a huge head start. That requires these manufacturers to either take expensive guesses, obtain reliable information from well-placed sources, or just wait for the phone to be unveiled. Since the last is not an option, and the first is too risky financially, the mock up could be presenting a realistic look at the size of the iPhone 6 screen and the device itself.
We have a video of the mock up along with various photos for you to view in the slideshow below.
source: Macotakara (translated) via RedmondPie