OK, I just started checking states at random.
Texas:
Dallas KLIF-AM 570 11a-1p
There you go. A major station in a big market, and a live clearance to boot.
Except, KLIF's schedule lists a different story:
http://www.klif.com/ONAIR/ProgrammingScheduleWeekends/tabid/259/Default.aspx
10am - 1pm The Glenn Beck Show
(And really, for all of Glenn's warts, this is a no brainer.)
Here's Fred on the KLIF schedule:
Saturday
8pm-10pm The Best of Fred Thompson
Sunday
8pm-10pm The Best of Fred Thompson
Not exactly choice clearances. The station runs Rusty Humphries and Alex Jones before him, and infomercials ("Plastic Surgery Today!"), for crying out loud.
There are two other "Dallas" stations listed, but I assume those are micro market stations elsewhere in the Dallas TV ADI.
Let's try another huge Texas market, Houston. From Fred's list:
Houston KPRC-AM 950 10p-12a
Ah, a major talk station in a major market, even if delayed late into the night.
Looks like he still has this one:
http://www.the950.com/pages/sked.html
Tennessee. He does well in his home state, and even manages an hour live clearance on the biggest FM talker in the state, WWTN:
http://www.997wtn.com/Onair/FredThompson/tabid/174/Default.aspx
FRED THOMPSON 12P-1P AND 11P-12A
His first live hour (11 AM-noon CT) gets clipped by the last hour of the local Michael Delgiorno show. Fred's followed by another TN native son, Dave Ramsey...I believe Dave started his radio career on the station.