Best Choose – GORUCK GR2
GORUCK GR2 – pricey. I haven't used a gr2, but I do have one of their smaller bags, which I have abused. A couple hundred miles of running with 6 bricks in the bag, plus a GORUCK challenge (google it) – no real wear, it's broken in so nicely. The color isn't as sharp, but I attribute that to swimming in the Hudson River with it, taking it through some other questionable water, and washing it. I also ran it through a warrior dash and shrugged off barbed wire like it was nothing.
Edit – the color isn't as sharp as when it was new.
Heres a few maximum carryon backpacks for travel:
Look at Tom Bihn Aeronaut http://www.tombihn.com/travel_bags/TB0906.html
Red Oxx Sky Train http://www.redoxx.com/Backpacks-Daypacks/Sky-Train/91019/160/Product
If you want really comfy straps – the MEI Voyageur http://www.meivoyageur.com/
Or dirt cheap (but not really BIFL) Campmor Essential Carryon http://www.campmor.com/essential-carry.shtml