I noticed you used a pretty good amount of laser cut metal for the structural components and chassis. If I may suggest, I think you might want to test out fiber glass or even lower grades of carbon fiber. Vacuum form plastic would work as well, but you would need pretty thick stock and heating source.
The only reason I suggest these is because I would expect them to be much cheaper for small scale manufacture once molds and cut patterns or cutting dies are made. I could be mistaken, but I think they would meet the strength, tolerance, and precision needs of the design in many places.
Edit: My mistake on the materials. I had read another website's news post before coming here and didn't read up before posting.