You found it!
The story is that it's thought to have been built by Warren Geddes, who worked for Glasspar, though it's not known if it's actually based on a Glasspar or not. It's certainly resembles one in some areas but not in others.
Either way we'll call it solved and if more information is forthcoming (and the site I got it from are trying to get Bill Tritt's son Matthew to say if he knows anything about it) then I'll post it.
Well found!