I remember 10 or 15 years ago you could pick one up for about $10 they were that common. Now you're looking at up to $250 for a good one!
Apparently the supply of these is nowhere near running out up in places like Germany, Austria, and in Switzerland itself, but the major surplus wholesalers in the English speaking world seem to have run dry.
I simply wasn't interested in one of these packs ten years ago, so I didn't pick one up. I finally found one locally a few months back at an army disposals store (surplus store) when I was in Sydney town for a long week end of whisky bars, strange Asian food and hotel roo... never mind...
I knew a bit about them before I owned one, but I am genuinely impressed and a little shocked at the quality of manufacture. My goodness people, these things must have cost the equivalent of a coupla hundred bucks to manufacture in the first place! I don't feel so bad about dropping $100 on one.
As a bit of an aside, this pack demonstrates a lot of the design elements you find on a modern backpacking/hiking pack. Internal flexible frame, fully adjustable suspension - it has load lifters - and it even had leather loops sewn on so you could retrofit it with a padded waistbelt for hip loading, making it even more like a modern pack in use. Impressive.
Here's a few pics of mine.
