Filter cubes are a great way to cheaply filter a lot of air, but they're bulky and noisy. Elevating them can get them out of the way if you have a high enough ceiling, but it's still not ideal. What if we built something around a device that is intended to be up there: a ceiling fan?

Let's say your blades are a foot from the ceiling, and sweep a diameter of 52". Shroud the fan with a regular octagon of 12"x24" furnace filters, and the air will flow in through the filters and down:

Relative to box fans, ceiling fans move a lot more air for a given level of noise, because they are so much bigger. Since noise often makes people turn air filters down or off, a quiet high-volume filter that doesn't get in the way could be very useful.

You could make a simple one with duct tape, but it should be possible to make one that is reasonably attractive if you used a metal grille for the outside. This could also make changing the filters much easier, if the framework held the filters and allowed you to slide them into place. Putting lights on the inside and using the filter as a diffuser could also have a nice effect, like a paper lantern.