I also rode a Kirk several times.
I worked for a Japanese company in bike stuff and fishing tackle,based in Sakai near Osaka.
When I was there for business, I used the Kirk, the only frame that suited me.
One time I visited the HQ again and couldn't find "my" magnesiun Kirk anymore.
I asked around and found out that they needed the Magnesium material for the first prototype(s) XTR rear derailleurs. :-(
Ha! That's an awesome story.