On the 2 Panels I own, on the Interior side where the rear window would normally be... there is a window indentation in the plastic panel.
Was looking at that thinking of installing a stretchable web-netting within the fake window frame.

Before I started my search for various netting that I could use for project, wanted to see if anyone has already done similar and what material?

For my little business intended plans, being able to hold papers, iPad, or not overly bulky material at an easy to grab location on the inside of door seemed like a handy small storage spot.
I was looking at the Ft Seat Back Netting, that could probably be adapted pretty easily too, just find a few salvage seat backs.
I think Northern Tool or similar carries netting that could be cut to fit... drill some holes in window panel section, add some grommets, pass the netting cables through and tie off behind.

 

 

 

I don't know if this can be useful. Found at Jo-Ann fabrics by me.
https://www.joann.com/utility-fabric.../10173359.html