removing wall or body support under rear seat

Backstory: I removed my rear seat a long time ago because I don't bring more than one passenger in my jeep ever and I made a flat support for a memory foam bed in place of the seat. It is out of wood and I can store tools or camping supplies under the bemch/support/cabinet/whatever thing. I am looking to swap the wood for metal and have it all welded up. So essentially the rear behind the front seats will be completely flat.

Now question: The wall or part of the body that is bent up and spot welded to support the rear seat and I assume add rigidity to the entire body is kind of in the way to store larger things undernearth. Can that wall be removed and that area just braced up like with a low profile box tube or is it vital to keep the wall intact? Thanks.

The primary function of that panel is to act as a gusset for the front leaf spring mounts, which are directly beneath it. It does very little to support the rest of the body in any way. You are fine to replace it with something that will provide similar support to the leaf spring mounts. It doesn't necessarily need to be internal. A 2x6 rocker reinforcement tube welded to the front of the box with perhaps a doubler on the bolt face to get a good tie-in between the two would be plenty. The floor pan does nothing... One thing to keep in mind; the floor is not flat there, there's a bump to clear the leaf spring eye. No biggy, just FYI...

Run uni stiffs and the weld in poly spring hanger box and it would be more than stout.

How much lift are you running?

If you are high enough not to need the tunnel for your driveshaft you could do like this guy and really gain some real estate down there: