I would be interested in that too. In fact, I know I mentioned it in a posting perhaps in May or June this past year. Perhaps you were referring to that post?
This past April, I made detailed measurements of the "new" style mojone employed across Galicia. I also obtained a scale drawing of the actual design. But the scaled drawing did not have measurements. So, I obtained them myself. Taken together, there is enough information for someone with the necessary skills to reproduce a mojone to actual specifications, albeit in some material other than granite. I understand the used ones might be available in Spain. But shipping would be prohibitive.
So, I brought a metric tape measure with me on my failed Madrid camino in April 2016, and measured several new mojones to get the exact measurements. My original thought was to develop a two part (top and bottom) hollow, mojone using a stone resin type material. The purpose of the two hollow segments was to allow the segments to be nested for shipping.
The left - right arrow would be reversible using screws from the inside, as would the ceramic "concha." There exists a difference of opinion of which direction the concha should point. I am of the school that says the point of the shell where all the lines converge should point toward Santiago.
The distance plate would be provided un-engraved with directions on how to correctly replicate the typeface with an engraver, and how to determine the distance from your situation to the official distance measuring point. That measuring point, or Km Zero, is the bronze disc in the center of Plaza do Obradoiro, in front of the Cathedral in Santiago de Compostela.
The actual granite mojone is exactly one meter tall from the top of the flat base. Being able to nest the two segments (top and bottom), means a ton of savings in shipping. Again, my original thought was to have one point of manufacturing and sales distribution in Europe and another in North America.
My goal was to have a near exact replica of an actual granite mojone in my garden, with a mileage marker custom engraved to read 6,603 Km to Santiago from my GPS coordinates, to those in the center of the Plaza do Obradoiro. As my garden view is exactly to the south, the arrow, and "point" of the concha, would both point left, towards the east, Europe, Spain, and Santiago de Compostela.
If anyone is interested in an informal joint venture, let me know. I have the ideas, the photos and the measurements, but not the technical knowledge or skills to convert my measurements to a prototype, let alone production. Based on my original "marketing" idea, my thought was to have a North American and European production point, based on identical specifications.
That said, if someone has come up with a way to manufacture a one-off, "granite appearing" mojone at home for personal use, I would be interested in that too. The ceramic concha, arrow, and distance plate are the easy bit. The difficult part is actually building a 1:1 replica that can be shipped. THAT is the rub here...
You must admit, it would make the most unique garden ornament and a daily inspiration to do another Camino, not to mention a really innovative and unique conversation starter for guests.
I hope this helps.