It seems like the knives in the Kinshiro type gauge could be more easily made by a hobbyist if you did a two-piece manufacture, like the larger cutters for the Veritas router plane. I don't know the best way one would do this, but it's just a thought. Being able to nestle two cutters inside of each other is really the bit that makes it a little more difficult, I suppose.
" Be willing to make mistakes in your basements, garages, apartments and palaces. I have made many. Your first attempts may be poor. They will not be futile. " - M.S. Bickford, Mouldings In Practice