I’m wondering if a spoiler or wing around the upper edge of the roof would reduce aerodynamic drag? A more rounded shape to direct airflow back down? Could also be a roof rack bar or a led bar.
What do you think about the option to sleep in the cab?
I think that would be better then something on the back. Glass roof, Netflix, heating/cooling and the Gear can stay as it is on the back.
I hope it will be possible to fold the seats flat somehow so 2-3 people can sleep there.