Has anyone experimented with stringing a cheap parachute silk or nylon hammock below your sleeping hammock as a vapor barrier/gear storage?

I have a Clark North American that ROCKS, especially in the cold. The storage pockets that are built in are awesome, but anything can be improved on. I tried this in November in the backyard, but have never given it a true test - I only hit 21 degrees one night. I don't know how it would work with a bottom entry hammock like the hennessy, but it was incredibly cheap and easy to string up a silk hammock that I already owned, throw a piece of 1/8 closed cell foam with glued on reflective material which is my normal Hammock sleep pad (courtesy of American Science and Surplus - I love that place) in the BOTTOM gear/vapor barrier hammock, and I was toasty for 3 straight nights with a 0 degree bag.

The only extra weight or gear was the 10 oz or so of the silk double hammock that I used as the bottom vapor barrier/gear storage. I suppose if I sewed the one side of the second hammock to my Clark NA, that it would reduce any chance of cold air infiltrating my vapor barrier and make the setup considerably easier. But it would mess a little with the gear pockets built in to my Clark, and make them accessible from one side only.

I hear a lot of talk about underquilts - is this just a poor man's version?