Hi Tieball. I live in Houston and can't offer you advice about growing Bald Cypress in Michigan because I've never done it. But I do know they are grown as landscape trees in similar climates to yours. And I know Don Blackmond, a member here, grows some pretty nice ones in your state. My guess is that he gives them some winter protection, but I've never asked him. So my suggestion is that, if you're interested in growing one, don't write them off until you've had a chance to talk to Don and get his advice about growing them in your area. You could send him a PM, or contact him here:
http://www.gregorybeachbonsai.com/index.html
When I'm trying something new in my climate, I always secure an inexpensive test subject and grow in my garden for a few years before I sink more serious money into something nice.
I've been growing BC in Northern Va. for about 20 years. Although we don't get the drastic sustained cold that you all do in Michigan in the winter, but we do get subzero and single digit cold snaps between Jan. and Feb. and sometimes a lot of snow.
I provide my BC with deep mulch cover (6-9 inches at last) over their containers, after putting them on the ground in late November after leaf drop. Other than the mulch, they're left uncovered. I've overwintered them this way since I started keeping them. We've had some deep cold in that period. The trees have experienced more than a few nights of subzero temperatures, blizzards and winter weather. They haven't had any problems.
The trees I have were collected in Louisiana and Texas, which I think is an important point in trying them further north. I've had Florida-collected BC too. I've overwintered those side-by-side with the La. and Texas trees. The Florida trees inevitably die or, in one case, killed outright, by below 25 degree temps. In my experience, Florida-collected BC tend to have awl-shaped foliage like pond cypress, rather than feather-like foliage in Texas and La. trees. Or they have a combination of the two.
If there are nurseries in your area selling the species, that might be the best source. BC is native all the way up into Illinois and is listed as cold hardy to zone 4a (which probably means in a container it's hardy to about 5a)
http://www.clemson.edu/extension/hgic/plants/landscape/trees/hgic1033.html
Local nurseries MAY be using a cultivar that's more cold hardy than the main species -- check established, reputable nurseries. Forget the bargain basement variety.
I believe you can successfully keep BC in your area, provided you give them some winter cover at the root zone and probably overhead (like in an unheated garage, covered cold pit, etc. Starting off with an inexpensive test tree is a very good idea. Get an idea of what works before taking the leap.