i just got my "nessmuk" pack made by frost river. (as i understand it, frost river was formed by a couple of duluth pack people who left when duluth got bought out by someone. my pack actually did arrive from duluth, MN)...
i will say this: these packs are beautifully made...really quality stitching, fat, heavy leather, heavy brass buckles, excellent brass riveting...but man, they are NOT designed for comfort! at least not if you're used to modern tech-nylon internal framed packs.
they're basically just rucksacks with a couple of straps over your shoulders. load them up and they pull on your shoulders...i can see why some fellers have said they're primarily for canoeing/portaging - i'd be miserably carrying a heavy load for any distance...some models have tump lines which are probably very helpful for relieving strain on the shoulders.
i really like my nessmuk pack for what it is, what i got it for: just a day-hike bag, something i'd take with me for hunting or what not, loaded up with some essentials, lunch, a sweater...i wouldn't want to carry more than 10-12 pounds in it, though.