I want to put a metal cabinet above the windows in my kitchenette. As you all know, I'm trying to avoid wood, so I'd like to build it out of metal. (I assume I'm not going to find prefab metal cabinets that are only a foot high.) I'm planning to use metal ceiling tiles for the surface, but what's the best material to use for the structure of it? Also, what's the best way to go about attaching it?