Kelty White Phantom

Ultra expedition pack made of Spectra. Extremely light (4.0 pounds) and durable. Previously hand made in small batches solely for high altitude expedition work, now can be obtained over the counter. White pack (Spectra can't be colored). Make sure that you get a later model (if used)--pack has gone through a number of upgrades. (This means gold trim and webbing, not blue which was used on the first models.) This pack will easily carry 50 pounds and feels great.

My main/only complaint is the minimal sizing. My Large size pack does not properly fit--needs someone about 6' 2" or 6' 3". Since few stores will ever carry these (most go to very serious expedition climbers), get one size on either side of the one you think you'll need if buying it new, pick the correct size, and send the other two back. (Be prepared to pay full retail price, but then that's what you'll have to do to get a near ultimate pack designed for a very small number of people who bet their lives in part on the quality of their gear.)