As I've been planning (lately) to build a box for my Honda to run it more quietly and store it while traveling. The current military plastic locker I was planning to use because it is strong and we have it, is a little too long. So I've done a little searching for aluminum solutions instead.
Stumbled on this and now I want
https://www.rvgeneratorbox.com/
Called, no answer...got a call back. The boxes start at $400, made in the US, .080 thickness (I think), access port in top for refueling, vent on side for exhaust.