Well, actually, that style of "pizza bread" is common enough in Western PA/NE Ohio, and is exemplified there by a place called DeRosa in Newcastle. The same general kind of pie is available in my home town of Tampa, from the Sicilian-Cuban bakery Alessi and is there called schiacciata.
However, the best versions of this genre of pizza are made a little closer to home: Grand Avenue, Western Avenue, and Taylor Street, in Chicago by, e.g., D'Amato, Masi and Ferrara, e.g. Or if you'd like a less-good version, try the traditional pizza with breadcrumbs and grated cheese at Pompei.
I'll admit, the Western PA version of this is a little different in that the bread is dense, almost like Jamaican doughbread and sauce quite sweet, paste-based. My mom's always bringing the stuff from PA, and while it's a little apples and oranges, the D'Amato's wins by a landslide in "Pepsi Challenge"-style throwdowns.
Take a look at Mike G's opus on this same,
often discussed route (quite possibly the most heavily traveled long-distance route in the country, considering it connects two of the nations' three largest cities and has lots of urbania in between). You could do much worse than lamb at Mr. B's and some custard at Forbush's.
Further north, a few places in or near Sharon PA might be worth checking out, including the original Quaker Steak and Lube, allegedly famous for chicken wings (the nuclear wings are indeed among the hottest things I have ever tried, though not especially good) and Combine Brothers, an Italian roadhouse serving massive portions of pretty good food.