Dan,
I know that at least 1 was build. I had a lot of discussion with Kevin Robinson about the rifle. I was seriosly thinking about building one. My biggest obsticle was to get the barrel from Krieghoff, our gun laws does not make it easier. All the cases are hand-made and expensive.

I have the origanal article Kevin wrote for Magnum magazine. If you are interested in the article, send me a mail and I will gladly forward it to you.