Sorry Marcellarius, this sounds auful cold, but, when someone asks me to make a pattern it belongs to them only and It?s up to them to decide if they want to share it. They may be making the Intarsia for someone who is paying for a "One of a Kind", so they don't wish it to be mass produced???
When I make an Intarsia for someone, who is paying me to do it, as far as I?m concerned the pattern, along with the intarsia, belongs to them and I won?t make another like it.