Our travel/tool box is home made from marine grade plywood. The wife's suitcase fits nicely, along with a hefty tool box, jack and other odds and ends. My suitcase is a old Samsonite that I've coated with bed liner and used silicone gasket maker to make it fairly water tight. We also carry heavy duty garbage bags for rainy weather.
The Luckenbach sign is now mounted on the box as well.