If you want the best available take a look at Kifaru and Stone Glacier. They both are designed for 100+ lb loads. Take a look at the Rokslide website. There are lots of reviews on different packs. The Kifaru website has gobs of videos on their line of packs.
I've been using and abusing my Kifaru for years for dall sheep, bighorn, mtn goat, elk, deer, antelope, moose, turkey...etc with excellent luck! Packed out gobs of critters out of hell hole type country with extremely bulky, hefty loads. Once you have a kifaru frame you can switch out several different bags. Kifaru also offers a large selection of accessory, lid, and add-on options that you can personalize your pack. I would recommend a 6000+ cu in bag. You can always cinch down smaller loads with a large bag but if you don't have enough room you are screwed with a smaller bag plus frame! The new pack/frame materials are so light weight so there really isn't that much of an advantage hunting with a daypack. I prefer to pack out a full load on my first trip back to the truck after harvesting a critter so that is another advantage to hunting with a larger bag and a frame capable of 100+ lb loads.