I'm feeling progressively better about the mechanical design, and spent some time on a day off piecing it all together in Rhino from the *.stl exports. Here is the machine minus nuts and bolts and belts and controllers, assembled and exploded into the four rigid assemblies:

Okay, not technically _rigid_ assemblies; what is rigid, after all? There are flexures everywhere, designed in and otherwise! And bearings, and rotating parts, etc. But these four main groups make it easier to discuss machine subsystems.

In any case, I just bought Rhino for myself and it is fabulous! The program is a different way of thinking about CAD, but after spending a few hours pushing parts around I'm quite happy with its flexibility for creating exploded assembly drawings. And there is so much more! NURBS, and Grasshopper, and all the rest. For now, it's a nice way to compose illustrations; the built-in pen view mode is lovely for complex mechanical things. I've had access to Rhino through various institutions in the past, but only used it sporadically for specific tasks; some recent encouragement pushed me to finally take the plunge and I'm excited to keep playing.

A few more view captures:
It might be time to figure out an easy way to add little dashed assembly lines to these exploded views.