Urban Spoon manages to combine nearly all of my interests (if only fancy shoes and early 20th century paintings were somehow involved...) in this post exploring the relationship between the prevalence of steak vs. sushi restaurants and political leaning in particular cities (via Freakonomics).
It's not perfect, of course -as the post points out - but it's interesting nonetheless. If I had more time and energy, I'd get into this on a more detailed local level, making district-based comparisons. Maybe it's because I live in a state where there are a lot of pockets of blue, a few pockets of red and a TON of pockets of purple, but I think that if you broke this down more locally, you might get different results.
Because here's the thing: in 2004, my district was split almost evenly between Bush and Kerry. However, while I don't think Towson is home to a single "steak" restaurant, there's about 1 sushi restaurant for every 10 people in this town.
I'm sure there are a million reasons for that - it's a college town, it's fairly young, maybe steak restaurants perform better in "downtown" locations while sushi places are equally or more successful in suburban places, maybe sushi restaurants require less of an investment in terms of decor (the ones around here aren't that pretty, at least) so they're less risky.
But if I had a dissertation to write, this could be a fascinating jumping off point.