I know there's not a lot of resident Michiganians on the forums, but the info might be useful to somebody.
Better late than never, the Michigan legislature passed a law over the winter allowing Restaurants with wine licenses to offer BYO/corkage!!
It was a fairly under the radar decision, and I know some restauranteurs who have no intention of offering corkage in their own establishment, at least not yet. Most restaurants haven't even thought about it, but I'm sure that will change as the summer rolls along.
I thought it might be useful to start a rolling list of establishments that do offer corkage.
So far, the only one I've heard of is Mission Table on Old Mission Peninsula (corkage $15/bottle).
If you hear of any others, I would welcome an update to the list!