Earlier in the thread I did a few posts showing a mounting system for the side of the hardtop, these are a few photos from one of those posts:
I was thinking about the uses for something like that so I did some idea drawings. On the left are rails alone - I used bright aluminum for this illustration but black anodized would be less visible on the hardtop side. In the middle a Molle panel is mounted. On the right are two large cargo bags.
Next are some fuel/water options - jerry cans and various Rotopax.
And this next one is a hard shell cargo compartment with a swing down door/table (or it could swing up). The compartment could be several inches deep or deeper depending on what it was intended to hold. On the left there's a Molle panel inside so pouches could be kept out of the weather. In the middle is a tool board. And on the right a net is used to retain various cans and bottles.
The other day I posted a photo of an external compartment, it's the third photo in this post:
https://expeditionportal.com/forum/threads/land-rover-ideas-for-jeeps.218029/page-15#post-2839820
None of these would be difficult to construct, and the rails are an off-the-shelf item. This could do both the top and bottom rails on one side of a JKU:
https://www.uscargocontrol.com/Airline-Track-48-Piece
The rails would be bolted in place (drilling in the hardtop required) but any of the cargo solutions shown above would attach to the rails when needed and when nothing is needed the windows are unobstructed.
This idea seems like it might be more useful and versatile than the products on the market that replace the windows with a fixed panel for mounting Rotopax containers. More different things could be mounted using it, it wouldn't require removing the window glass, and the window wouldn't be obscured during daily driving when you didn't need to have expedition gear mounted.
What do people think of the idea?