In reply to sip a cup: The only one that comes anywhere near to what you want is the new Arcteryx Muira rucksack combined with the Pali rope bag. As usual with this supplier very expensive but excellent quality and design. I wish I could justify buying one.
All the others tend to be too much of a compromise and either a shoulder bag or a big lump on your back. I have a DMM one which is relatively comfortable and you can get a good deal of gear in it but you cannot zip the bag up when the tarp is extended making it useless for lugging the rest of your gear around at the base of the routes.
millet do a huge 60L expedition pack with a zip right down the front of it like a duffle almost.
good pack for trekking and climbing and not bad as a rope sack when the lids stripped.
ive used one a lot as an access rope bag - feeding the rope into and out of the top. definitely handles the abuse.