McMaster Carr has old style steel storage boxes (like current Proto Set Boxes) in various sizes for not allot of money ($10-$28 depending on size). I recently bought a larger one for storing some 1/2" sockets, and they're great folks to deal with.
http://www.mcmaster.com/#tackle-boxes/=glzoo9
Since you need your sockets to stay organized while moving them, you could either put them on a rail and find an appropriately sized box, or customize a box with cut closed cell foam; that might be a good option as well, and a fun project (they'd be less likely to rattle, etc.).
I'm not sure who manufactures these boxes; mine doesn't have any identifying marks. It's steel, painted red, and is plenty burly; everything I've gotten from McMaster Carr has been US made and of very high quality.