other good choices: Arcteryx Khamski (or Khamsin 38), Lowe Alpine Rondoy and Vision 40, Marmot (I forgot the name of the model, but it is about 3000cu in), Dana Designs Bomb Pack. Noth Face also makes a nice pack about that size in their technical series. I have a Marmot Eiger (smaller than what you are looking for, but very comfortable) and a Dana Designs Alpine (larger than what you are looking for but also very comfortable, and you can kind of retract the sleeping bag compartment and make it about 3500 cu in.) I've been impressed with the construction and detailing on both. Arcteryx has a fantastic reputation, too.