Hey mate, just a suggestion but have you considered looking at pre existing pelican cases or fishes cases. If you find something close to what you want then you could modify it to suit ie Stencil logos and such on.
For cabinets and lockers if you wanted to make your own, my suggestion would be to go to the drawing board, figure out your dimensions then head to the hardware store. Im sure you could make some killer weapon lockers for relatively cheap.