Bookworm, your request may be a little harder to fill due to the remoteness of your location. But there are certainly a lot of circus endeavors in Wisconsin. So, fear not, I'm determined to find you something.
Still, if you can at all get down into the Madison or Baraboo area (even just occasionally like for a summer camp), that is probably going to be your best opportunity.
Here is one group which is in that area:
MMAC ~ Home
If cross state is at all of an option, there is Juventas in the St. Paul/Minneapolis area.
The Midwest Clowning Association convention is in October this year in Occonomawac (sp?) and they have a really good Junior Joey program, so I'd encourage you to attend that, if possible, too.