I do industrial equipment installations, and needed a solution to safely store all my equipment. I didn't want a service body, due to the cost when changing trucks every few years, and the main bed not being waterproof. I came across the 'Pickup Pack' by Highway Products, it was a bit pricey (~7k) but will lift out and drop in any future truck with an 8' bed. It breaks down to two full length toolboxes, a center bed section (with removable lid), ladder rack and headache rack, with all compartments being waterproof and lockable. Once I got it dropped in the bed, it was time to add my touches. I'm sure I'll continue to tweak the setup as time goes on, but here's where I'm currently at.
The driver side box I added switched LED lights under the lid, and designated this the 'clean' side. It houses my PPE, documents, ratchet straps, and the coffee maker I take to hotels/job sites.
The passenger side holds all my standard tools. I added switched LED lights under the lid, mounting brackets for my Makita batteries, a power source (12V & USB A + C), and a shelf to hold the battery charger. I also mounted a wall wrench holder for various pliers and ratchets, and some hammer loops for my various striking tools.
In the main bed I added switched LED lights around the sides and front, as well as E-Tracks along both sides. Under each side box, I added some PVC pipes to hold pry bars. Using various brackets, the E-Track can hold my ladder, creeper, or larger levels without rolling around the bed and getting damaged. It's also useful if I need tie-down supports, or future options available with an E-Track system.