When the article opened, I thought 'looks like the one that was at Barber Motorsports Museum'.
Last paragraph confirmed.
It was a bunch of years ago that we were there. (8 or 9). Maybe it was a different Frankenkawaski?
https://www.barbermuseum.org/the-museum/barber-story/
If in the area it's a very interesting place to visit.
Be sure to take your camera.
Same location outside Birmingham as the Barber Motorsports Track.
https://www.barbermuseum.org/plan-a-visit/getting-here/
EDIT:
The one we saw was also an Allen Millard creation.
It was a pair of air-cooled Kawaski's married together to create V8 1600.
The write-up beside the bike said his next project was to marry a pair of KZ1300's - presumably resulting in the project in the article wvmandingo linked.