Cabela's, Cabela's, Cabela's.
I took a regular old Cabela's Alaskan Outfitter external frame pack and loaded it up with 50 pounds, walked on the treadmill at the highest incline for 5 hours a week, 4 months in a row. For 2 more months I loaded it with 72 pounds for 5 hours a week.
It'll handle...