When I get my HDPlex 400W DC-ATX and I can make a rough model for it, I'll make a few adjustments and print my first prototype
Keep in mind, the first prototype won't have vents and I'll be threading the plastic instead of brass nut inserts.
Basically, the motherboard gives the frame it's rigidity and mounts in a way you've never seen
Here is a rough SketchUp model of HDPlex 400W DC-ATX.