You can get a mini AG doll at Barnes and noble and cut of the shirt part then you bake a cake that's half a sphere . Once baked cute a hole big enough to fit wast down. Ice the cake the way her skirt was designed. Now stick the doll in you can let her hair down too!  Deception by Mackenzie Armes
American Girl Birthday Cake
American Girl Doll party ideas: Question and Answers
As far as I know I am the only one to have made an American Girl cake with a short dress.
Mini American Girl Doll Birthday Cake
lots of birthday cake ideas
American Girl cake based on the dining room in the store in NYC.  6" and 9" tiers, iced in buttercream.  Decorations are MMF.  Black piping gel used as accents on the name and the flowers.
Adorable cake and cupcakes at a Fairy Garden Party #fairygarden #partycake