This is another one of those things that growing up, I just thought you could get everywhere. They are rare enough outside of the midwest, and nonexistant in the rest of the country, at least in my searches. There are a few places in Minnesota that have them, famously The Gopher Bar in Saint Paul, but they are not the omnipresent food that they are in metro Detroit. Some of my favorites back home would be Lafayette in Detroit and Lapumas in Rochester Hills.