I am a huge fan of the Jeep Gladiator, and would really enjoy getting to own one someday. However if you are someone that does already own one, you probably should just go ahead and buy one of these DECKED bed organizers.
These bed organizers fit perfectly right into the bed of your new truck, and allow you to have sliding drawers to keep things locked up and safe.
However unlike most bed organizers, you can continue to use your bed (almost) like normal.
Basically it fills the bottom of your bed, and gives you a surface on top to continue storing things that you normally would, instead of taking up a ton of that usable space like you would with a normal tool box.
These DECKED boxes, are weatherproof, secure, and can handle up to a 2000 pound payload on top of them, meaning you can still use your new Jeep to haul not only your tools and gear, but also those dirt bikes or 4 wheeler without an issue.
I definitely recommend you take a look at the video below, as this is for Mid-Size trucks like the Gladiator.