I have often thought about, for my basement, putting up a "shelf" (for lack of a better term) on three sides of the wall, to have a "two tier" display. You could display kits all along 3 sides of the wall (in a "U" or "C" shape) on the floor, and then double up your space above it and do it all again. The problem I think would be, securing the shelf to the wall and making it stable. To display a kit in it's "ready to play" position (with of course the batter side of the bass drum being all the way against the wall-no pedal attached), the shelf would need to be about 18-20" inches deep to allow for the thickness of hoops etc.
I guess you could secure it with braces underneath? I would love to try this! Medium Density Fiberboard might work. Depending on if you displayed cymbals/stands at playing height, if you had high enough ceilings, you could maybe do three tiers all the way around. That would be cool!
Has anyone ever tried the "shelf" method? I would love to try this, but the ceilings in my concrete block basement (built in 1947) are only about 7 feet tall, so that would be tough, unless I put the shelf at exactly 3.5 feet and just lowered toms and cymbals as needed.