I would investigate a quality internal frame or even frameless backpack from Gregory, Kelty, or the like. I don't know what brands are populous over the ocean, but I'm sure both of those would be available.

I think that in the case of a major societal breakdown, one may not want to have what appears to be "military" looking gear. I have heard of people's O.D. green canteens and BDUs being confiscated in Africa as well as South America after some moderate harrassment. I would think this kind of event to be a small chance, but...

Also, the others here are right. An ALICE pack is heavy, uncomfortable, and outdated.