A lot of people bought nice gear way back when and never even used it. Within the last two years I've picked up a brand new Calif-made
Kelty pack that just sat in someone's closet for decades, as well as several brand new vintage Camp Trails US mfg packs - all of these cost
over $200 way back in the 70's, but I got one of em at a garage sale trading for a half empty qt of marine varnish. These were way better
built than packs nowadays and I find them suitable for almost everything except as an airline carryon. For the latter application I have a good legal-sized airporter pack with shoulder straps tucked away. It will accept my Ebony 4x5 system or a 6x7 system, including my Gitzo carbon-fiber tripod and filmholders. I wouldn't want to do any serious backpacking that way, however. Now all I gotta do to be really in style for old
age backpacking with a vintage Kelty is to replace the handle on my wooden ice axe. Alas, I too opted for a modern fiberglass version after
taking a particularly interesting downhill exodus. The point of the old wooden axe and half the shaft have been inadvertently donated to
mountaineering posterity, still up there somewhere... Then a couple years ago I took a good dunking in ice water when one of my nice new fiberglass trekking poles snapped during an early season ford, so newer tech isn't always better! Fortunately, I keep all my photo gear, clothing, and sleeping bag etc double-wrapped in big plastic garbage bags just for such incidents.
I loved my F64 backpack with the side pouches for the film holders. It is way lighter than the lowepro's I've had.
Photo backpacker is about to release an updated line of packs. You may want to check them out.
Lowepro Flipside 400 or 500; it's very comfortable to use all day, and holds a lot of gear while keeping a small profile.