I was recently in Chicago and had my first Italian Beef sandwich at Mr. Beef. Basically, it's like a French Dip made with a spicy beef and slathered on with hot peppers and dunked in the beef cooking juices. It was phenomenally delicious.
Here's a greasy little photo:
I'd gander that with NYC's big Italian community this should be easy to find but I've never really seen anything. Have I just not been looking in the right place?