I just remembered that I once read where someone made a frame out of 2x2s, he made a square then placed screws every 3" or 4" apart, He then used 12 gauge fencing tie down wire and wound the wire around the screws to make the screen, He then cut 4 more lengths of 2x2 to the level he wanted the screen to be at, and screwed them to the screen as legs thus eliminating holes in the drywall.

This might work for you situation.

JG