I've been looking for one of these aftermarket, and all along Newmar has them.
The only ones I could find aftermarket were in the $300 range.
Newmar price $148.
Fully articulated to position to the front or to the side.
I got the last one in stock and it was marked "passenger side".
It was easily converted to the "drivers side" by removing several set screws and reversing the parts. This puts the adjustments facing you instead of the windshield.
Using the mounting base as a template, I drilled four 1/8" holes and used black 1" #10 sheet metal screws.
Newmar part # 40019, Sunvisor RH 7.5x18.