Steve Sando emailed to make two things clear that aren't either in my post or Bittman's article—that there's a difference between dried corn and dried corn that has had its skin removed (which is called hominy).
"The Mexicans exclusively use dried corn that hasn't been prepared and it's a lot of work and that's why they compromise and use the yucky canned. My posole/hominy has had the skin removed by being soaked in CaL. It's been done already so it's kind of more than just dried corn.
"And this is the real confusing thing: Posole with an S is American/Southwestern/Indian and refers to the grain and the dish. Pozole with a Z is always Mexican and referes only to the dish.
"There was a study done on why heavy polenta (ground whole cornmeal) eaters in Italy were having bad gastro problems while the Mexicans, who consume much more corn, were not. It was the skin. And it turns out soaking in lime (CaL) adds a major nutrional boost so it's really an example of a processsed food that's better than the whole grain."
Steve also said you could use a food processor to make grits, but that seems like a blade destroying idea. I think a coffee grinder would do the trick.