I had a few minutes while waiting for something to load, so here's a quick idea.
The box is 2' x 4' by 4'-6" high including 3" casters. It includes two simple 6" box drawers at the bottom for "wig accessories" and other stuff. The case is "two wigs deep" to give it a more stable base and help keep it from tipping over. The base, sides, and top are 3/4" ply, and the rest can be 3/4", 1/2", or 1/4". I allowed 14" between shelves but it's variable. The dowels keep the heads from sliding around, assuming they have holes on the bottoms. A hasp on the front and metal chest handles from Lowe's or HD on the sides complete it.Hope that helps.