Are 40 galon or more galvanized tanks still available?

Looking for 40 gallon or more tempering tank

It would seem that the 40 or more gallon galvanized pressure tanks we use to run would make a pretty ideal low end tempering tank for budget radiant systems if they were wrapped with a decent R- value covering.

When I search for them online none show up. Is this an item that has gone the way of the dodo bird? Is a cheapy electric water heater my only low end option?

Thanks for any informed replies.

Hugh

yes that does seem Crazy, or even Cheesy. but i guess it all maybe does depend on the situation.