My preference is internal framers for hauling heavy loads. Many of the external frames the load is situated several inches from your back and heavy loads tend to shift and torque your back...especially in steep terrain, sidehills, crossing deadfalls, boulder fields, etc.
You may want to take a look at overall weight of the pack. Badlands 4500 is a super heavy pack for it's size. Obviously the more pockets the heavier the pack (more zippers, material, etc). A heavy pack like the 4500 may weigh a couple pounds more than other packs that can actually haul larger, bulkier loads.
Kifaru just came out with a pack system that weighs less than 3 lbs. It may be worth a look? It appears to have a nice harness system but I'm a little leery about the outside material holding up to punctures and sagging? It also starts at around $550 without any additional pockets.
I currently have an Arcteryx Bora 95. It is a humungous pack and has a similar harness to the Kifaru mentioned above (it almost looks like Kifaru copied them?). Arcteryx is a fraction of the price of a Kifaru. I've had mine for over 15 years and never had any seams or material go bad. Mine is a bloody mess from all the elk, moose, mtn goat, sheep, deer and other critters I've hauled out with it. Mine weighs around 6 lbs but is super durable and dependable. Mine isn't camo or quiet cloth but I almost exclusively use it to pack camp and meat.
If you are pinched for cash you can usually get killer deals on new or nearly new packs on Ebay, Craigslist, etc. Also, mountaineering shop websites often have 20 to 30%+ off coupon codes.
