Have you checked out the Bearikade "Weekender". It's made from carbon fiber with aluminum end caps, has a capacity of~650 c.i., and weighs 31 oz. according to the manufacturer. This makes it the lightest canister this side of the Ursack, which is also an option you might consider. The Weekender is very pricey to buy, but the company rents them for a very reasonable price($5/day for the 1st 3 days, and $2.50/day thereafter; shipping is $14 to theeast Coast zone). As far as I know, they have never been broken into by a bear. Their URL is bearikade.com. Good luck, whatever you choose. You're facing a very formidable critter.