Help identifying metal resonator guitar

[Bruce Zumsteg]

I believe this to be a rare metal resonator guitar, however there is no manufacturer's name or mark, nor is there a serial number. All pictures that I can find of similar National brand guitars, have square 'portholes' on the upper portion of the body, where this one has round holes in that area. Also, note the deep metal neck surrounding the wooden fretboard, and the irregular hex shaped border around the resonator area.

Any information that someone can share regarding the brand, and estimated value would be appreciated.

Resonator - body.png

Resonator -side.png

Resonator - full front.png

resonator - back.png

[Noah Miller]

I've never seen anything like it. The leg cutout on the neck is a nice touch.

[Eric Dahlhoff]

That is really cool looking! Not an original National of course.
It's hard to imagine that someone went to all the work to make just a one-off.
Maybe a prototype?

Value would depend on how it sounds and plays.