I don't even have ancestors in Michigan and I'm trying to get into this site.
Miriam Robbins Midkiff's blog mentioned a back-door approach to the Michigan death certificates that are currently on and offline.
Visit here:
http://haldigitalcollections.cdmhost.com/cdm4/search.php
Miriam's blog entry is here with a few more details, but this link should get you in.
http://ancestories1.blogspot.com/2009/03/sneaking-in-back-door-getting-michigan.html
Actually, my wife has an ancestor who was in Detroit in the 1720s, but that's a little early for vital records.