Interesting stuff. But it is beyond debate that the Midwest, and certainly the agreed pounded pork loin hotspots of Indy and Iowa were and are heavily German-American.
Google 'Indianapolis' and 'German,' and up comes an unsurprising history of Indy's (and Cincinnati's) German connection. From IUPUI, in fact.
http://www.ulib.iupui.edu/kade/indianapolis.html
So maybe pounded, breaded pork loin is not remembered as German in the drive-ins and bowling alleys of Des Moines and Carmel. Maybe if they were called something more German-sounding, like, um, hamburgers, frankfurters, or pretzels, the connection would seem less speculative.
I'd venture that plenty of pizza is served in the same towns, but not necessarily by Italians. (Apparently, only Chinese-Americans have a lock on selling their own food, no matter where, no matter how bad, and no matter how Americanized.) Many here might agree that the various Midwestern sorts of pizza, from Starback to Imo, are much less Italian than a schnitzel on a bun is German, but few would deny the Italian influence, indeed even the muddied, possibly debasing, but ultimately direct genealogy.
Anyway, none of this is meant to diminish the remarkable documentary you are creating, and I will be sure to take a look at your list before hitting the road. I love, pounded, breaded pork, whatever it's called.
And I like the bars where they are served. Really, you should try Resi's. It sure looks like it was decorated by the same guy who did the bar with the world's largest breaded pork loin.
P.S., the Bohemian place in Westmont is, well, Bohemian, though I'm not sure how different the schnitzel of of Prague is from that found across the border. And the point about Leinie's is exactly what you suggest, except more narrow -- what Midwestern beer made by a German American familiy isn't sort of German.