Lynn
Did you try these guys? They’re probable the largest manufacturer in the world for manholes, water valves and all kinds of other related steel products. I bet you have a dealer locally that could get you what you want. They are one of my former customers based in Northern Michigan and have foundries and sales outlets around the world.
Note they have a foundry in Ardmore, OK.
https://www.ejco.com/am/en/products/...2522Round%2522