Checked in 6 large wine shipping boxes from LAX to LHR after a visit to napa earlier this year...all made it, no overweight charges (on BA at least) and they even came on the baggage belt first.
Just get a decent shipping box (with polystyrene inside)when you buy it, gaffa tape it shut properly, and make sure check in puts a fragile sticker on it.

I have to say, i have a large wine collection with all sorts of weird and wonderful varieties, but i have never tried wine from michigan...i am intrigued...