One sheet of 1/4" luan plywood and a couple of 2x2s or 2x3s cut to size make a fine playfield shipping crate. It's sturdier than a box, not subject to excess dimensional charges, and allows room for rigid foam on front, back, and sides of the playfield. Also makes it damn near impossible for a shipping company to bend/break the playfield. And it's not as heavy as you might think.