Installed the smallest, lightest interior shelf unit I think I've seen in a 4R.
Seems ridiculous but I've been always wanting to add a shelf in this spot. Summer, the fridge/cooler lives on that side of the cargo area and I'm always looking for a little extra space (but keep minimal and open).
Saw something similar on a van dwellers Youtube vid and found this:
Amazon.com
Surprising nice sturdy ABS plastic.