You want to protect your precious Raspberry Pi board against short-circuits, while keeping access to all connectors ? This enclosure is made of two acrylic glass plates and metallic spacers. No glue is needed at all: all parts interlock, including the board, and 8 screws keep them in place.
If you interchange top and bottom plate, you will be able to mount on top of the enclosure a USB Micro-Hub from Yoctopuce, and up to 3 three Yoctopuce devices, allowing your Raspberry Pi to interact with the real world.
Yoctopuce offers the design of this enclosure for free, under a Creative Commons Attribution-ShareAlike 3.0 License. Cut file is available here (CorelDraw format), all parts list can be found in the blueprint.