We are in the process of building 2 flatbeds, which we will be turning into service beds. They'll have underboxes in front of the wheels. Contractor boxes on top, running down 2/3rds of both sides. Then we may stack another box on the driver side, and a rack on the passenger side for milk crates. And then top it all off with a pipe rack.
Everything will be bolt on, and my bed will be designed so the boxes can be taken off easily for whenever i need a flatbed. Also going to try and make it all low enough to easily clear a gooseneck.
I'll see if i can dig up some pictures of our old fleet of trucks with utility beds.