This post isn't a Land Rover idea, but as long as I had the rack on the Jeep I threw the roof top tent up there to see how much extra storage the extension provides when the tent is up there.
In this next photo I've got a cargo box on the extension. If I turned the box around so that it opened from the rear, it could be accessed from within the tent.
The shoe caddies are installed on the side of the tent base, I posted about them earlier in this thread and they're visible in the photo above.
The changing room is a DIY project I made from a set of canopy tent side walls I picked up at Walmart for $40.
I posted earlier in the thread about the Sand Ladder Ground Anchor project, FWIW here's a view of where I carry the sand ladders - I bolt them to the base of the main rack under the tent. They slide out the side of the rack when needed.