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.
Deeds can't dream what dreams can do. e.e. cummings