I think the most practical option for an inflatable bottom hammock (if an inflatable hammock bottom can even be proven practical) would be in my opinion a hammock body and bottom shell made out of Cuben.
I would use SGTRock's Cuben Ghost Hammock but make the body with the 1.0oz Cuben and the bottom with .75oz Cuben.
Body - 5sy @ 1.0oz/sy = 5oz
Bottom - 2.5sy @ .75oz/sy = 1.875oz
Down - 4oz
Total = 11oz
I just don't know. I don't know how the tape will hold up. Someone has made an inflatable pad with Cuben so it should work. Taping the darts I'm sure would be tricky if even possible.
I just don't know if it's worth it. My gut tells me that a down UQ is THE way to go. It's proven and versatile. But I can't help thinking of how nice it would be to have such a light, small, and minimal set up.
With regard to the hammock sock portion of this build plan, would you think that the sock covering the bottom of the non breathable Cuben hammock would be redundant? Or would it still be retaining heat radiating out the bottom of the hammock? I can still see how it would be beneficial. Although there is no exposed UQ for wind to strip heat away from. It's now an enclosed inflatable.
Thanks for the input!!!