have a definition. I'm not trying to argue with your idea -- I admire your willingness to do a tremendous amount of hard work (which is, I believe, the definition of "non-profit!!").
I teach history, and the term "middle class" frequently come up in the course of conversation; and is usually accompanied by considerable argument over what it is to "be" middle class. We are, presumably, a classless society, and many people hold firmly to the idea -- not by denying class as a whole, but by continuously expanding the definition of "middle class." Although many, many of us are closer to being part of the "working poor," there is still a desire to keep up with the Joneses -- and that means claiming the "middle class" at the very least.
Considering only income, this article may help, as it summarizes things rather neatly:
http://www.factcheck.org/article249.htmlThis article takes a stab at the sociology, if that helps:
http://www.washtimes.com/specialreport/20031129-105855-7412r.htmBest of luck with your venture. My son is in the process of starting a non-profit in Oregon -- and I am constantly amazed at the amount of work involved. I wish I had a quarter of your stamina!