I believe that dirkvl added the "Leather maybe?" picture only as an example of a keyboard which seems to be put in a kind of leather bag. And to display its Qwerty layout. I think we here don't need to think too much about the functionality of the phonein the leather bag (the 1st picture). Besides, to me it looks that if the keyboard half turns 180 degrees on its "leather hinge" onto the phone, it covers only the small "back camera" (that for Skype etc). Of course if you turn the keyboard so that it goes behind the phone, it would become an obstacle for the main camera. But that hardly is the intention.

In this context it is better forget the way the Sliding Keyboard Half works, on its rail which slide the phone in front of the keyboard. I believe that dirkvl intented this thread maybe for the Qwerty layout and material issues. Although you are right about the keyboard if it slides on rails below the phone, please do not worry about the "keymat layout sample" picture.

Besides, a solution has already been found: the hidden part of the sliding keyboard (like those of N810 and N900) can be equipped with one or two holes thru which the cameras "sees" the object. Via the latter link of my previous reply you can read more about it.