I built one 2 years ago that stays in 75% of the time, not the same things you are carrying but I have my compressor and reel, handyman, expanded metal area for jugs, Delta drawer box and a small cpl on my skid. Takes 5 minutes to take the forklift and have the bed empty, fit's fairly snug, I used some boards for shims so that on different trucks it would still fit if they change the beds over the years...hopefully. I decided the other day that I would kinda like to build a smaller one just for the portable welder that could be set in a truck or on a trailer or on top of my drawer box when needed so I may tackle that eventually.