Much of my stuff that I sell privately is B&W. I really enjoy working in mono, various shades ... I do have a few B&W's in the micros.... not big sellers at all, but they do sell. One of a wingback chair in my mother's Victorian living room moves quite a bit. And one close up of my daughter-in-laws pregnant belly seems to move.
Don't think anyone will be making big money in the micros with B&W. As someone mentioned, if an art director wants a B&W, they'll find a color image that suits them and convert it themselves.

=tom