I got the Duluth Rambler waxed version earlier this year in their St Patrick's day sale, don't think they still sell that bag now though? But yeah its very tough indeed.
Anyway, to answer Dave's question regarding comfort. You have to ensure that the bag is packed correctly as there is no back padding, so either a blanket, or folded thermarest as the back padding is essential. As for the straps....they are a lot more comfortable than they look actually - although I'm sure it depends on how heavy you make the bag. I've used it for extended weekend trips where I've carried it into the woods for a mile or two and it is perfectly comfortable, even more so than my old snugpack bag which had padded everything!
Wouldn't pay the price that Tamarack are asking though!!!!