There is another one at the Landmark Mall, I forget the name. It's a stand, not really a shop.
The W Hotel is opening (probably already has) a cupcake counter at the cafe, and the Hyatt already has it at 'Biscotti'.
I saw a stand at this weekend's Food Festival for 'Rose's Cupcakes' - a home business that is soon opening a store in Al Sadd.
So it seems that the business of cupcakes is slowly finding its ground here, although the extent of their popularity remains to be seen - based on how well these businesses end up doing :)