This boat is rarer than I assumed. I posted a query at the Fiberglassics.com forum and it turns out that the Royal Flush boat pictured here is one of two ever made.
I suppose it is possible, perhaps, that it's sister craft, the Queen Mary Lounge, may never had existed beyond the planning stages or first prototype.
These two pictures were taken at a Beloit, WI boat meet around 2005.
The current owner of this 23 foot craft hopes to start restoring it in the near future. It has been stored indoors for the past several years.
This futuristic craft was last run in the water in the 1980s and according to it's owner it handled very well and was built around 1970 by Space Craft Corp., probably located in the Los Angeles area.
The owner believes the one pictured in the 1970 Powerboat Annual with two steering wheels was probably a prototype.
The one pictured here could be the revised version because it has one steering wheel and appears to have been built on a production line.
It was rumored to be in a low budget spy movie. I'll see if I can find out which one.
According to the owner's post at the Fiberglassics forum this went through at least five owners before falling into his hands.
Here is a photo of the boat surrounded with about 18 years of growth behind Big Bill's Autoparts salvage yard, Newport, MN. All you can see is the ball hitch.