The problem with those cases is they are steel and over time they will rust and have problems. If they are going to be exposed then stick with aluminum, you also get a weight savings. The bed of a truck is probably the worst place for power coated steel as it gets banged and knocked continually which exposes bare metal.
Personally I have always used Zarges cases, you can get them in all sizes even custom made sizes. Fortunately when I got the camper mog it already had all Zarges storages boxes, one was missing so I replaced it, but the existing cases are all 19 years old and been on the truck for its entire travels and still work like they are brand new. If I buffed them they would also look brand new.
One down side is most of them are top opening so they work as a chest and not as draws, If you mounted one sideways it would probably leak. You can get lots of insets for the cases to compartmentize them.
I am considering getting another and modifying it to hold a running Honda EU2000 generator.
You can find suppliers all over the web.
Rob
