There's a sort of Sterns-like piece in the new Martha Stewart Living (November 2002) that singles out road food in places they've done stories over the last few years (no prison comissary jokes now). It seems like a decent enough list-- to take my old Kansas stomping grounds, besides the fairly obvious Stroud's in Kansas City they get the Cozy Inn in Salina, home of a proto-30s-style White Castle-like hamburger (I had a Cozy Inn bumper sticker on my Honda for many years), so that's pretty good.
But I have to admit the Chicago choice is a bit curious. I think I've even seen this fairly recently but it's unknown to me culinarily: Poochie's, a hot dog stand in Skokie. Anyone know it, anyone think it exceptional?