Down clothing question…

It might work OK, but likely to be much heavier to get the same wamrth. Methinks you'd be better off with something like the Nunatak Raku if you want to go down that track, as the feet, head, legs and arms are all accomodated in a single 'baggish' design which increases thermal efficiency.

I've wondered this myself – if there are peope who hang around in camp in their down gear, and then just lie on a pad and hit the hay. Perhaps just hopping into a bivy? Maybe some hardcore mountinaeers?

FWIW, I use an Arc AT (3/4 sleeping quilt which reaches to just under your armpits) with a down jacket and hat for warmer temps. Problem is, my AT weighs about 10 oz, and has got to be a bunch warmer then any 10oz down pants.
I would also think, that if a pair of down pants is enough to keep you warm at/all night, they are probably overkill for use while at camp. And if they are required to keep you warm in camp, then they probably wouldn't do you much good as a primary sleep system.
I do know that many, including myself, will combine their down garments with their sleeping bags to extend the range of them.
Steve

Personally, I am afraid of wearing down clothing while hiking as I sweat too much and I would probably render the down useless from my prespiration. However, I carry a down vest for camp. I wear it under a synthetic jacket (Patagonia Micro-puff). It adds a lot of core warmth for very little weight (7 oz.) and bulk (softball size).

Also, down booties are popular for winter camping. According to the posts here, the Cadillac of booties are made by Feathered Friends.