Well, the usual way I've seen people deal with this is either open up the case and leave the extra drives dangling to the side, or just lay them on the bottom of the case (or on top) and don't move it any more.

That works. Though, if you want to imitate that... Pay attention to the temperature of the harddisks. There is no air circulation if you just lay them flat on the floor and they might get too warm.