From what I read, at least in some places it's only the 1 gallon
containers that are banned. 5 gallon and quart containers are still
available.

And everything oil based is harder to get these days since almost
everyone is using latex for everything (even stuff they really should
be using oil based paint for). I have not previously heard of anyone
having provlems getting oil based polyeurethane though. I live in one
of the offending states and have no problem finding gallons of oil
based polyeurethane.