It's not accurate to say that Fox News has "hardly" mentioned the election. Greta van Susteren (who is from Wisconsin herself) has given enormous coverage to it, and I have seen segments on it on both O'Reilly and Hannity. And the conservative web fundraisers hit my email ten or more times a day urging me to send them money. (I'm not sure how much those fundraisers actually ever send to the campaigns.)
But there's no question that unions have thrown enormous weight around for the Democrats. This could, however, be a last hurrah for the unions in Wisconsin. They have initiated one recall after another in an effort to undo the 2010 elections. The public has to be getting sick of it, and they know who's filing these recalls.