I admired a traveler who used a very sturdy box to transport video camera, housing, fins, wetsuit, etc. Apparently it is called a Balikbayan box, but I can't find a seller in the US. These folks in the Phillippines produce both a wheeled box, and a cover with handles that can be used on a 20" x 20" x 20" box: http://www.lugmaxbags.com/travelbags.html
The wheeled box is especially cool, with corrugated plastic instead of cardboard. I'm sure I'm not the only one who might have some moist gear on the return trip... Does anyone know where to get such items?
Double-wall corrugated boxes in the right size is of course easy: http://www.pkging.com/Doublewall-Boxes-20-20-20-275
Check this out: