The most upsacale place I can think of is the Bell Tower Inn. Pretty small, so it would not have the amenities of a larger hotel, but nice and a great location adjacent to the Univ of Michigan campus.
Marriott also has a resort in Ypsilanti, but I cannot remember the name. Ypsi is about 10 miles east of Ann Arbor.
I'm sure someone else will mention a place I haven't thought of.