Benchwork construction began with 20mm x 40mm extruded aluminum.
First step was to cut the t-slot extrusion to length (yes, we moved everything out of the way before we turned on the saw):
But even more important than anything else, the module frame is "Rule 0" compliant, so it will actually be available for use in a setup:
Here is a view of the underside— those blue components are secured to the sides of the module frame, and allow the top to be fastened from below: