In Michigan, try Ensemble in West Bloomfield or Audio Dimensions in Royal Oak. Both of these are just north of Detroit and are listed in the yellow pages. Ensemble specializes in Levinson and BAT while Audio Dimensions has Audio Research and Theta.
Harry at Audio Dimensions is one great guy. I spent an afternoon with him and it was very enjoyable. His knowledge is second to none and he is the polar opposite of a "pushy salesman". Call him, make an appointment, and plan on making a friend.