Hi Don,
I must tell you, ever since 1965 I argued with friends about fabrick vs metal skin.
In fact, I tried to design a big glider, about 10 foot long and 16' wide based on, ahem, the big 1 litre beer cans. I got snagged on on forming the wings, -then family issues happened-, but I still think you have a great idea.
I encourage modelers to sidestep traditional suppliers and go directly to plastics wholesalers. A sheet of 0.020 styrene as you suggest is a bargain at about US$40 or less a sheet.
I can't take model airplanes out to fly anymore, but I'm working on a solid styrene aircraft, at least for the parts aluminum can't conform to, and hope to fly it, or at least watch it sail into the side of a barn.
Hey, the vac thickness styrene is incredibly strong and light, and completely overlooked.
Thanks for your post,
Bockscar