The big external-frame pack has not quite gone the way of the dinosaurs, but for all intents and purposes its extinct. The last serious effort to turn out a competitive external-frame pack came seven or eight years ago, when Dana Gleason of Dana Designs put out some external-frame packs. I still have one that I bought on a closeoutit consisted of a Dana Designs Terraplane bag attached to a really excellent metal frame. For packing big loads, it is a great pack.
Kelty Tioga 5500
Kelty still makes a few external-frame packs. Its Tioga 5500 ($170; kelty.com) steps right out of the 1970s, with a rigid metal frame, big padded belt, and comfortable suspension. Rated capacity is 5,500 cubic inches, but thats misleading. You can strap stuff onto it and easily carry another 1,000 cubes. The Super Tioga has a little nicer bag, but its also a touch smaller. Its being closed out for $140 at Campmor (campmor.com).
Cabelas (cabelas.com) also makes decent external-frame pack called the Alaskan Outfitter Pack. One interesting feature on this pack is a sort of shelf that folds down and extends out from the bottom of the pack. Carry a half cord of firewood there. Price is $209, and rated capacity is 5,300 inches, which again is up for interpretation.
And that, my friend, is just about it. Prowl around for a Dana Design K2 Longbed pack; maybe you can find one used. A guy in my area has one on Craigslist for $200.
Check out the new 2007-2008 Winter Outside Buyers Guide, packed with reviews of more than 300 new gear must-haves. Its available on newsstands now.