Hi Galen,
Nice Build A Long! You don't state what the size of the box is, but I have seen and picked up several Higher End Cigar boxes that are approximately the size and shape of the box you are showing! Most of this size are made of really nice looking woods and have wall thickness of 3/8' or 1/2". So I think they would be a good option and save a good bit of work! I have used them for making "mini" practice amps for guitars. So to all interested, check out your local Cigar Stores!
Harry