I'm committed to building one of these and have started acquiring some of the parts. I'm going to be self-sourcing as much as I can because I have a laser cutter.
I also wanted to re-implement the design in FreeCAD so that those without Autocad Inventor would have some options. Each of the parts is a separate, fully constrained sketch. That means that critical dimensions can be adjusted fairly easily. FreeCAD doesn't have an assembly tool yet but it's coming.