When I was looking at backpacks at the Outdoor Retailer show last month, I was immediately drawn to the Granite Gear Nimbus Core. How couldn't I be? It's a hollow-centered, open-top bag with a keg strapped to it; it's pretty hard to ignore.
The new backpack is designed for backpacking in bear country where you need to carry your food in a bearproof cannister. The cannister slides in the center and several lateral pockets on the sides serve for carrying the other essentials of your trip. You can also stuff gear on top and then bolt it all down with the included straps and compression flap. If you happen to be taking a trek outside of bear country, you can use the middle compartment to store your tent, sleeping bag, pad and other gear--just be sure to keep it all in a dry bag because you don't get much weather protection from the open design.
I've never backpacked through heavy bear country so I don't have much experience with cannisters. However, this piece makes me wonder how people carried them before. Such a radical design aimed to hold one indicates it must be pretty difficult otherwise. I think you'd be better off with the old rope and bag up in a tree, but I guess in wilderness areas and parks that require cannisters, this backpack is your best bet.
The Nimbus Core weighs 3 lbs. 12 oz. and is recommended for loads up to 40 lbs. It will hit the market next spring at a retail point of $260. (Update: The Nimbus Core is now available here at Amazon and at other retailers.