I was hoping you'd see some decent results.
My spin on it will be using the top half of a trunk lid to make an extension. They're only $20 or so from the junkyard. Bonus points for a color matching one.
I already had two extra ones, all I did was cut out the bracing and the back half. The sides already have rolled edges and I left enough to roll the rear edge so it doesn't pose much of a safety hazard. I'll probably pop rivet it on the top and add a couple braces on the underside.
It can be extended further, it's about halfway on top of the trunk.
To fix the 3rd brake like being partially concealed I'll be adding a 4th one in the rear window.