I have a number of different pieces of Maxpedition stuff and can attest that they wear like iron. Maxpedition has a reputation of overbuilding their product and in my experience that is quite true. Well built and tough.
I have included a URL for some stuff that Maxpedition makes that seems to meet the needs of the OP quite well.
Bags/Cases - MAXPEDITION HARD-USE GEARŪ (Primary innovator and premier manufacturer of outdoor, hunting and tactical nylon gear)