I think with regards to the self-replicating angle, there's not really anywhere for the research to go. The Mendel is sufficiently self-replicating for any practical application of the tech, and the GUS Simpson is about 80% printed parts, with no rails or threaded rods in the mix at all. Until there's a breakthrough in printing conductive material, there's going to be a limit to the kind of components that can be printed.

Actually, why don't I see more interest in the GUS Simpson? Is it just so new it hasn't caught on like the Deltas and Mendels?