Thanks for the input! I've been backpacking in the Sierras for over 20 years and familiar with these ultralight down bags. I have a Mountain Hardware Phantom 32 for summer and an REI Kilo Zero for winter, both 800 fill down...as I get older, the bags get a little tighter. Just looking for a good warm, flannel, cold weather bed roll for base camp (no hiking)...to be continued
Here's some food for thought, Bax. If you just need a bag for base camp, no hiking, try just carrying a good wool blanket with a sheet (or soft wool), and take one of your good down bags as a comforter. Unzip it all the way, then put the wide end (the head end, unzipped) over your feet and legs. The foot box comes up around your neck. The wool blanket takes care of your upper toro. If you get cold, either put on a fleece hat or use a small blanket over your head. I use one of my bags like this at home every day. 3 season bag in summer, winter bag in winter. Note that I live in Maine, and home heat is not always easy to come by. Even if my bedroom is brrrr cold, I stay toasty all night. Saves some bucks, using what you've already got.
I use Rab sleeping bags and have been very impressed with them. http://s1274.photobucket.com/user/nathanshepherd1/media/IMG_3105_zpsed40050b.jpg.html][/URL]