There's a place called M2 Fabrication on the south side of OKC that sells the ones that drop into the stake pockets.
Thanks for your ideas! That gets me on the right track. Derail away. I love it when it comes off the tracks as long as it's actual information, not just childish arguing.
Bawer SS boxes are very light weight. They also have plastic parts in the T handle. Merritt makes a good strong aluminum box and have A SS door option.