I would guess it's built off the superstructure of either an X-500 or Artist Award with a sound hole instead of "F" slots.
Yeah, I'd guess the back/sides/neck are nominally Artist Award stuff. My memory of Hans' book is that the top is thick, solid flamed maple, like a Les Paul in that it's flat across the underside and carved on the topside only in effort to thwart feedback. I could be way off, though -- it's been a while since I've read up on them. I do wonder how well it works in the feedback dept -- I have a one-off luthier-made guitar that has a solid top that's an inch or so thick in the middle and otherwise unbraced and I find it has a long, ropey sort of resonance to it that actually loves to slip into that kind of cascading/exponential feedback. It sounds killer, but it's the worst feedback machine I own,
way touchier to manage than my X-700. It's hard to describe, but I always figured it was a product of having a lot of mass in the center of the top and less around the rim, making the thing sort of bouncy, for lack of a better term? Total sidetrack, though, and not a very scientific comparison.