I'll note that crosswise bed panels make more sense for many because of their utility for forward-facing benches and ease of storage otherwise. That allows me to slip off the center sections to leave useful bench/shelves when I need the center aisle or the option of folding the whole bifold back to the wall when the full span will be needed later. I happen to need lengthwise bed/bench panels since I clear the center aisle for long canoe carriage inside.

(I could have simply bolted the hinges to the carrier plates but needed 3' of spacing to allow room for the bed panel cushion when rotated to the vertical. On the bed side I bolted heavy L-brackets to the carrier plates and then sturdy hinges to the brackets. So I made wide AL carrier panels that bolted to the L-track threaded studs on the wall side. The desired bed support level was a little above the lower L-track.

I cut brackets out of L-extrusion and used threaded studs to support my 'airplane' shelves above the upper L-track.

It seemed reasonable to me to decouple the L-track locations from where I wanted the bed and upper shelves to be. Essentially all of my wall runs are located at the ideal sheet metal locations. 80/20 is a T-slot framing system that is easy to assemble and can be configured into endless custom solutions, from DIY projects to industrial applications. I might have more L-track in my van-3 runs each wall, 4 floor runs, 2 ceiling runs-than anyone else here.

8020 t slot wall structure