What about Kingston, Ontario? Great venue, best breeze on the Great Lakes, and the CORK regatta is very well run. The CORK one-design regatta is set for Aug. 22-24 next year.
Of course it's a bit farther away for some than WI, but, selfishly, I would love to see some U20 hype around the eastern/Canadian Great Lakes, to increase the chances that the two boats for sale in the area will stay in the region, and fall into the hands of some active racers.