What I wanted was something cheap that would stop all my stuff from sliding forward. It had to be easy to remove in case I needed the full bed and it needed to be easy to customize with extra brackets or eyehooks for tarp tiedowns or whatever. The entire project took 3 hours. That includes the trip to Home Depot for lumber, and finding all my tools for the job. Dividers from Toyota Canada will set you back around $400.00 each and they aren't really suited for my purpose. The adjustable crossbar in the pic keeps stacked boxes from sliding forward. Crappy Tire sells that for $50.00. The nice thing about this setup is the narrow storage area near the tailgate for stuff that you don't want to slide around or tip over (like kerosene or a six pack). The wood is easy to drill for an alarmed cable lock. My hard tonneau cover has lock handles and I have a Pop and Lock so this cable is more to keep the briefcase from sliding around too much.

Material list: 4 pieces of 2" X 4" X 8' spruce lumber and 1 package of 4 anti skid rubber bumpers ( 1" diameter, 1/4" thick with 4 screws included in the package).
Optional: If you want the middle divider, you need one more piece of lumber that's at least 43" long (I used a scrap of 1 7/16 X 2 7/16 stud material leftover from a previous project). My total cost for the materials was under $12.00.