My wife and I routinely bring back between 30 and 40 bottles of wine with us from Germany. The rules allow one or two liters duty free. That doesn't mean you can't bring more--you just have to pay the duty, which is not very much. Maybe 50 cents per bottle for wine. Hard liquor may be more. The limit is a vague standard "for personal use." I doubt you could carry enough in your baggage to cause any question on this. Our personal best of 43 bottles did not raise any concerns with the custom officer.
Here is the sample customs declaration form you will fill out on arrival in the United States: http://www.cbp.gov/xp/cgov/travel/vacation/sa...
The key is to declare how much you have. If you fail to declare it, it can be confiscated. If you declare it, the customs officer may or may not charge you the duty. We have never been charged the duty on the wine we bring with us. I asked once about this, and the officer indicated that if we had 40 bottles of hard liquor (e.g., schnapps) with us, he would have charged us. They don't much care about wine.
Technically, the liquor import laws also are governed by the local jurisdiction (i.e., the state), but custom officials are federal employees and do not have a lot of interest in state laws. Remember also that you go through customs at the first airport at which you land in the United States. If you aren't going through customs in Michigan, the officials at the airport are definitely not going to care about any Michigan tax laws.
It is not that hard to pack it. We buy the wine at the wineries and ask them to put it in the same boxes that they use to mail it when shipping wine within Germany. Any sturdy cardboard box should work well enough once inside a suitcase. Be sure that there is at least a piece of cardboard between the bottles. Once we allowed a winerey to package a box for us. It was taped shut and we never looked until we got home with a broken bottle--just a sheet of paper between the bottles!
Remember that you can no longer carry liquids in your carry-on bags. Bottles of wine, etc., must be in the checked luggage.
Also keep in mind the baggage weight limit. Liquids are heavy! Be sure you know your airline's restrictions and weigh your bags before you go to the airport.
Personally, I would recommend wine over beer or schnapps. There is a pretty wide selection of German beers available here, but it is hard to get good German wines at a reasonable price. If you take wine, take good quality (which, if bought directly from a winery, is still pretty inexpensive in Germany). Good wine is no harder to transport than bad wine.