Jim,
In Kansas, we also have a fairly up-to-date list of cities that have adopted some sort of code language. We're lucky to also have a great group of talented professionals at the state radon office whom likely have a comprehensive list as well. While it may not be currently published, I'm willing to bet someone in the AARST office has a national list compiled somewhere.

I would love to see A.F replaced with RRNC at some point, but we'll take what we can get for now.

Cheers!