I would be happy to make them and sell them, I would say about €50 for a finished piece. However I have posted all the plans online for free so people can make their own for about half that.
There are other plans and kits available online with buttons and dials to make adjustments, but the idea of this project was to do away with all that.
Also for the DIYers I have added instructions in the code, so it should be very easy to set up for different engines and shift points.