I like the idea of a fully print-in-place design too.
Perhaps a cone style hinge would work for this design? If you were to remove the pin holes but leave the conical cuts in the underside faces of the hinges, translate the cut downwards by vertical_clearance and turn it into a solid extrusion on the topside faces. I've seen a few 3D printed designs use this type of hinge and they seem to work quite well.
I tried poking around in the scad file to see if it was possible but I've got very limited experience with it unfortunately.
Anyway, great design. Thanks for sharing!