Looks like a good idea. I keep thinking something that would automatically move the trap out of the way when the door is opened would be cool. But I'm no engineer. Wouldn't even know where to start.
So there's a corner and a door...when you slide the trap out of the way, where does it slide and hang?
You have to reserve space for the trap to slide to and occupy.
I also have a corner w/door...and there would be no place to slide the trap. To one side is the wall, to the other is a piano.
The other option would be to hang the trap on the door...but it depends which way the door opens and if the trap will get in the way. The gobo w/wheels might be the easiest solution....