Anybody out there build their own guitar case? I have a few guitars in unusual sizes, and of course it would be nice to have the right size case, light and strong, for not much money. I'm thinking about building a case out of thin plywood, lining it with EPP type foam material, and covering it with fiberglass. Anybody else done something similar and have any hints? I have only modest woodworking skills and have never tried anything with fiberglass before.