Didn't mean to hijack (again), I was just curious.

I know that insulated tarps are commercially available. They use them when pouring concrete in below freezing conditions, ensuring a proper cure.

I've even thought of making my own insulated tarps. There are many situations where a waterproof layer with, say, R2 inside would be mighty handy. The only question is whether the inside layer needs to be fire resistant; that's a challenge.

A tent is more challenging in other ways. You have to think of moisture management as well as insulation. 'Course, a baby wood stove solves most problems.