Metal ceiling material?

I been kicking around a number of ideas for various materials for the ceiling of my cargo trailer. The latest one is to use the sheet metal that is used for roofing. It weighs about 65 pounds per hundred sq. ft. Cost-wise, I can get it for about $70 per square, cut to the length I need. The corrugations would keep it pretty rigid. Anybody tried it? Do I need to have my head examined - again?