I had this problem with a patagonia bag, so I chopped a seatbelt out of a taxi (it was headed to the scrapyard) and had a friend with a stout sewing machine attach it to the bag, along with a couple of adjustable pack buckles from an outfitting store. It's padded with a luggage pad. Now it's somethign like a chrome, but with a sweeter seatbelt buckle.