After bit of thinking and seeing some commercials ones I made one in 5 min.
Things needed:
Printer to print the protractor. File with size below: http://www.rcgear.co.za/media/useruploads/media/conventional-protractor.pdf
Cardboard
Some sticks/balsa or something and rubber band or something to clamp them in place.
Wire/solder for "indicator"
Pin/screw as hinge.
Pictures explain it all,
The pin keeps the protractor on the balsa sticks and small piece of "Press stick" keeps it in place.
At neutral turn the cardboard to show 0 degrees and press into place.
Behind the Scene:
Up elevator:
Down Elevator: