It is no great secret that my colleagues at Collabora have been doing work with the Raspberry Pi Foundation.
My desk is very near Marco and I often see him working with the various Pi boards. Recently he obtained one of the new B+ units for testing and I thought it looked a little sad sat naked on his desk.
The design is completely original though is inspired by several other plastic "clip" type designs I have seen. Originally I created and debugged the case design for my parallella though tweaking it for the Pi was pretty easy.
The design is under a CC attribution licence and I ought to say that my employer is in no way responsible for this, its all my own fault.