If you need more than this for your winter climbs up Whitney or Denali, then you're carrying too much. Enough room for a tarp, a few eggs, and your down parka:
Patagonia Atom Sling Pack. Like new. $55 shipping included.
Bonus: cell phone pouch to tell the wifey or dirtbag boyfriend "Summited Denali. Will be home in a hour. Get the steaks on the grill!"