Years ago I advocated a double wall inflatable frameless tent. I think they even make such a beast. IMHO, this would be a tremendous thermal advantage in extreme cold conditions. Imagine three pieces of rubber coated canvas seamed so that it has baffles that overlap (like HD corrugated cardboard). It might be bulkier, but it'd be tough, and it should, in theory, be awesome as a cold barrier. Very low thermal conductivity, waterproof, windproof, crushproof, and built in air mattress to boot.