I saw this link on the Chowhound General Topic board a couple of weeks back and thought I would post it here.
The PBS station in Pittsburgh has produced a series on 'great sandwiches of America.' It'll be coming to PBS Jan 8 (check your local listingsyadayadayada).
It appears to be heavily weighted to the Northeast (like Stern's roadfood.com) - 11 out of 20. But they've been to Thelma's in Houston for a BBQ beef sandwich.
I think WQED is the station that's done some really good shows for PBS on diners, hot dogs and ice cream; I'm looking forward to it.
On the web page, click on 'Places and Sandwiches.'