A Gregory Rock Creek internal frame pack that opens suitcase style, front zip, has been my go-to pack for mushing my stuff around for the past couple of decades. It's made of denser weave nylon than most packs use now. It's worn like iron and that's saying something becaus just out my door is the thickest scrubbiest wilderness of chaparral imaginable, which shreds most other packs quickly. I lined it with cut Ensolite foam that can be reconfigured for any of my gear from 35mm and now 4x5. The suspension system is excellent-- better than any large dedicated camera pack I've tried or seen. Have carried as much as 65 lbs of cameras, tripod and camping gear into the backcountry with it. Weighs maybe 2/3 what the purpose-built ones do.