Sounds like a custom need. Maybe draw it up and if you don't have a local metal shop; have SendCutSend make it for you.
If your main want here is anticorrosion resistance, I'd suggest doing a heavy black or dark color powdercoat instead. I'm talking about at least three coats, four would be better. That's now my SOP for battery trays, and while even that will discolor a bit over time, it stops corrosion dead in its tracks.
The one for my ‘55 Chevrolet truck is stainless and mounts flat. Not original but a stainless repro from Cl***ic Parts I think.
The Jalopy Journal
