Systemstech submitted a Bus Pirate v3.6 Sick of Beige design. His design has the board mounted on an inner ring with mounting holes, with the other sheets glued together.
All the layers are welded with solvent but for the last two the makeup the bottom lid and those two are welded to each other.
Four 4-40 or 3mm screw fits nicely recessed in the bottom lid. The screw holes on one of the bottom spacers needs to be tapped, also the board adapter. The bottom spacer that gets the tapped threads gets welded to the case.