Oh, wow, this is big news! I just found out that because it's been so popular, McDonald's has extended the Wizard of Oz Happy Meal promotion by a week. To accomodate them, Madame Alexander has quickly commissioned two more dolls, the Munchkin Mayor and the Wizard. They'll start showing up in Happy Meals on April 20. Here's the picture:
For more details, including all of the logistics of how they're going to pull this off, take a look at the article here.