This is a mash-up of a Ploopy Nano BTU mod and a CRKBD (original case on Thingiverse: https://www.thingiverse.com/thing:4589913)

At the center is the Nano and then off to either side are the Corne halves. This setup basically removes the 'split' characteristic of the Corne as they are attached to the base of the Ploopy Nano. The attachment uses a Hirth Joint which allows the angle of the keyboard halves in relation to the trackball to be set. That angle is then held in place by the threaded nut.

The standoff piece is to be printed 10 times and is what holds the PCB to the case.

The nano top stl can be found here on the creator's github: https://github.com/gbrnt/ploopy-nano/tree/master/hardware/mechanicals-btu-mod/STLs

This project also uses Socket Cap style M3 hardware:
4 - M3x8mm screws to attach the ring arms to the rings.
4 - M3x6mm screws and brass heat-set inserts to attach the hinge to the case bottom.
2 - M3x20mm screws and M3 nut to attach the hinge to the arm
1 - M3x6mm screw to attach the Nano top to the base
10 - M2x4mm screws to attach the pcb to the case.