I found this chart on Wikipedia, this is one of the more detailed breakdowns of the American classes that I have found. I don’t necessarily agree with the breakdown, but I am intrigued by it as well.
But since I posted the IRS versions of who are the affluent, the middle class and poor, I have had a number of conversations with clients regarding their definitions of the middle class. I am surprised at who consider themselves to be middle class. It seems practically everyone does. I have people who have rental properties, own their own businesses consider themselves middle class.