When I was in Iraq last January I noticed a lot of infantry guys carrying these old-fashioned rucksack style high-and-tight bags, sometimes with appallingly heavy loads. Maybe there's a specific military reason for it, but I can assure you that few serious civilian backpackers would use them, as they are absolutely crippling over any long period of time. Perhaps they are designed for young backs, or maybe they're designed to be easy to transport aboard helicopters and airplanes -- but packs that transfer the weight to the hips, rather than put it on the back, have been fairly standard tech for thirty years. I even had a frame pack once with little home-made inserts on the top to balance a canoe -- I could carry both the pack and a 60-pound canoe (for short distances) as long as the weight was on my hips.
My go-to travel pack is a Victorinox roll-aboard briefcase which I have customized (with a box cutter) to take a small but high-quality Nikon kit, a laptop, and, just as important as the Nikon, all the other stuff that business and educational travelers must take with them. Having a carry-on devoted to cameras is fine, but it's a category populated by lots of bags. A missing bag (I even wrote to Think Tank about it) is one that would accommodate not a huge professional system, but a small high-quality system for use by business travelers. Business guys, who are also photography enthusiasts, *must* take a lot of stuff not related to photography: a laptop, cell phone, notebooks, pens and pencils, eyeglasses, spare eyeglasses, sunglasses, noise-canceling headphones, medicines, etc. It's surprisingly difficult to find a full-sized camera case that can be customized to take a smaller system, and then add this other stuff. That's why I wound up with the Victorinox -- it turned out to be easier to customize in the other direction, i.e., from business case to camera case. But it would be nice to have a case that was designed from the start to carry a small high-quality system (a body, three or four primes or a couple of zooms, a battery charger, spare battery, spare memory cards, Arctic butterfly) as well as a full business kit.