So, at work I happened to notice one of the boxes our metal powder comes in, it's a 3/8ish plywood box with metal corner braces. Conveniently it is also .863x.28x.43 meters in size, remarkably close to that of what Ryan and I have been building (1x.3x.4x). I'm going to bring one down so we can look at it, but if we like them, we may be able to get a few of these pre-made boxes a month.
Feel free to comment on the box at the space (should be there today or tomorrow) if we don't like it, it is free after all 