The idea of paying more for intra-Japan transit than the actual cost of airfare from MKE to NRT didn't appeal to me. I've decided to stay in Tokyo for the duration of my visit. Thanks for your suggestions, though.
If anyone is interested in a FlyerTalk gathering, see my post in FlyerTalk Community.
http://www.flyertalk.com/forum/Forum95/HTML/000220.html