American Girl Crafts has everything you need for girls with American Girl dolls to party together - even the cupcake stand. http://www.grandmachronicles.com/2012/02/my-early-start-with-toy-fair-2012.html
Keep an eye out when you are in thrift stores and flea markets for things that can work as doll tableware. These shot glasses are a tad bigger than scale but were 25 CENTS each!!! The plate was part of an assortment of small plates, 7 for $3!