In MI, the state licenses are controlled by the Liquor Control Commission and the Department of Agriculture. You have to get a winery license from the LCC, and a food processor license from the DoA. The food processor license is annoying, as you have to build a facility to their specifications. Check to see if your state is the same before you even consider a meadery. That right there can be cost prohibitive.
The BATF no longer handles licensing of alcohol producers, that is now handled by the TTB (Alcohol and Tobacco Tax and Trade Bureau).
http://www.ttb.gov/ Everything you want is buried in that website.
Short version:
You pay $500 annually in a "special tax" just for operating your winery, whether you are making sales or not. You are not allowed to start producing your first batch until you've got their license and have started paying this tax. You pay an excise tax on each bottle you produce. If you get your licenses, pay your taxes, and keep good records, they leave you alone.