I believe I have a solution for my hanging my screen 10" off the wall.
I would take a pic to describe what my situation is, but let's see if i can verbalize it first.
I have a wood mantel that sticks out about 9". I have things like a clock and pictures on the mantel, and a large picture hanging about 20" above the mantel with a large oak frame.
Now, I will be building a 15:9 ratio screen using Polywall, framed with baseboard type wood, roughly a 48" x 82" screen.
I finally figured out how to make this hang off the wall such that I could quickly remove it and stow it in another room against the wall when not in use.
I plan on mounting a cross beam on the back of the screen horizontally from the frame side rails, about 25" up the screen from the bottom of the frame. I then will be mounting two eyelet bolts at the 33% and 66% points on that cross-beam. I then will be mounting picture hangar wire between these two eyelets with alot of slack.
On the wall in question, I will put two white hooks under the picture on the wall, just long enough to clear the framed art just enough to get the wire over them to hook on. The idea is that gravity will want to pull the top of the frame off the wall toward the floor. The bottom of the screen will be resting on the edge of the mantel making a pivot point.
I then only have to adjust the wire in the eyelets to the point that the screen sits almost perpendicular to the wall, suspended by the wire on the two hooks under the framed art, and resting aginst the edge of the mantel on the bottom.
To remove, just lift up and unhook the hangar wire on the screen from the two hooks and stow away.
Probably as clear as mud. I hope it works, it is just a concept at this point.
For mounting over a window, I am not sure. Could you mount a couple of brass L-brackets above the window, and hide it in a valence of some sort, then hang the screen from those brackets with decorative chain and hooks on the screen frame?