Ogsarg, I have a 24R with a TV in the rear bed area. It is mounted on the passenger side of the RV about the same location you would need to mount yours. It is in the middle of the wall. This creates a problem for what you would like to accomplish.
The arms on the swivel that I have are approx 8 inches long each. This prevents the 19 inch TV from clearing the edge of the wall when attempting to rotate it 180. If the swivel arms were longer or the swivel moved closer to the wall inside edge the TV would stick out past the wall edge when stowed normally.
I know this is not what you are looking for, but it might give you some ideas.