I asked Mediadevil about the difference between black and white/red nexus 5
I hope you are well and thanks for getting in touch.
The black and white Nexus 5 have a slightly different curvature, and as our cases are designed to fit very snugly to the device itself, this means that a black Nexus 5 will not fit into a case designed for a white Nexus 5. In addition, the black Nexus 5 has a soft-touch back as opposed to the harder plastic back of the white Nexus 5, which adds friction when it is being inserted and removed from the case, and we have also had to take this into consideration when designing a case for the black Nexus 5.
At the moment we are completely sold out of all colour combinations for the black Nexus 5 except for the slate/pink option, however we do have new cases in production, which should be available by the middle of March. I'm afraid I don't have a definite release date at the moment, however please feel free to get back in touch in a week or so, as we should be able to give you an update then!