Six Moon Designs has some excellant packs yo might want to look into. I have carried a Starlite for a few years. On a seven day trip I carried about 35 lbs with a good level of comfort. I wouldn't want to push it any further than that. They also have a panel loader that seems to be well thought of. Ron's packs are made form the same Dyneema as ULA packs if I'm not mistaken.
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Deeds can't dream what dreams can do. e.e. cummings