Skeleton Box
Here's another idea for a Raspberry Pi case: two scraps of perspex and a handful of nylon spacers
The spacers are 25mm x M3. The PCB supports are some spacers cut down: 15mm(top) and 6.4mm(bottom) with 1mm of padding)
Don't build anything from that picture; the top support should be closer to this side of the board than the far side.