While searching for some information on lead mining in Wisconsin, I came across a new search engine on the Wisconsin Historical Society's website featuring Turning Points in Wisconsin History. Here's the url: http://www.wisconsinhistory.org/turningpoints/
What led me to the page was an article on lead mining in Illinois and Wisconsin. I did a search for my McHughs and came up with entries for the vital records index on several family members both direct and collateral.
Click on the link to the home page and click on the explore our collections link from the green browse button on the left. That will take you to the WHS collections page where you can do a general search for your ancestors or search by collection.
I have used the WHS site before, but really like the new format. If you have Wisconsin people, give it a look!