Built in Under Quilt

I asked in another thread if an integrated under quilt would work. It seams that due to the stretch of the Hammock, not such a good idea.
So, I got to thinking, its not the under quilt I have the most problem with, its my feet get cold.
What would the problems be with doing a small integrated under quilt just in the foot box area. It should only add about 4 oz. to the Hammock to add quilted area 24"w X 30"l and 2.5 inches of loft in the foot box area.
I would thing there would be minimal Hammock streatch in the foot box, so it seems it should work. Then if the suspended under quilt moved a little during the night your feet would still stay warm.

It would be a lot simpler (and more versatile) to get a top quilt with an enclosed foot box, or some down booties. There are a lot of times when something extra integrated into the hammock itself would just be in the way.

Sounds like Risk's WarmHammock idea from a few years back.

http://www.imrisk.com/hammock/warmhammock.htm

On a related topic, does an uq for just the foot area exist? As mentioned above, a 24x30ish quilt that attaches to the main quilt and Ridgeline.
Either for supplemental support to a full quilt or to make a 3/4 into a full.