RuPaul's Drag Race

 I was just wondering, is Mariah the only contestant on the show who comes from (for lack of a better word) the proper ball scene, i.e. part of a house and having presumably walked drag balls a la Paris Is Burning? I want to say yes, because I know Shangela and Alexis have said they've competed in pageants, but do not hail from actual ballwalking houses the way Mariah does. IIRC, Alexis wasn't even familiar with the concept until she asked Mariah about her background. 

So does anyone know if Mariah is the first, or have any of the queens in seasons past also come from ball culture?