[wnhpblai] Modern mechanical cipher

Design a purely mechanical cipher machine which can withstand modern cryptanalysis.  Publish the design, allowing anyone to make it who has access to a 3D printer or other rapid prototyping.  The goal is cryptography for the masses even in the event of a crack down on electronics.  One step up from Schneier's Solitaire cipher but similar in spirit in requiring less specialized equipment (sort of).

Inspired by the Hagelin M-209.  Hand-cranked.