Let me first introduce myself, I'm Roy and I work for an injection mould tool design company.
I have made a preliminary concept design for an alternative to a case for the RasPi which would allow the holding and fixing of the board but allow full access to all the connectors.
This version of the 'clip frame' allows fitting direct to VESA 100, a smaller version without the side arms is also possible for projects where VESA fitting is not required. We do also have a clip together case in the works.
Depending on feedback, we may go into full plastic injection moulded production which would allow a much lower cost per item than 3D printing can currently allow.
Let me know your thoughts.