Why not find a local machine shop to make you one. The RIMS, DSS mounts are all 2" larger than the drum. Have them roll a 16" circle, then weld or make the tabs for you. You can buy the legs & mounts from DSS.

I had a buddy make some RIMS mounts for my old Luddies. A 13" with 8 lugs & a 15" w/ 10 lugs.. I had them chrome plated and can't tell the difference.