I Dont know the exact number but there are atleast 6 johnny mnemonic games being converted into The matrix games, that being known, i cant call it an one off product, it is an dutch project made by the now same owner of the dutch pinball museum!
It is more or less an prestige project which became an reality after years of in the making!
They couldnt being mass produced as the builder dont have the warner bros license to even do it at all.
But unlike kevin he didnt presold the game on a wide scale, what he did is made in or around ten games and sold them for 10K each.. And the project is done, he sold them to make a couple of co builders happy and some well known dutch buyers, and he got money back for producing the game, but i believe even thou it most have been a massive amount of work to build the matrix, i still believe that someone got paid!
And selling a converted johnny mnemonic into a P Roc the matrix game for 20.000$ is too much money IMO, but the owner holds the right to do so, good luck with that sell