Also late to the party, but I find this discussion fascinating; always something for me to learn from all of you! Can't say I ever heard anyone use "amn't" - unless of course I didn't realize it because of the pronunciation. I would have to agree that it just sounds wrong to me.

I weigh in with the "ant" pronunciation of "aunt," but my husband (born and raised, as I was, right here in metro Detroit) has always pronounced it "ahnt." I guess that makes it a familial rather than regional difference, since we come from very similar backgrounds.