I believe its the Yacht Club Bakery that Lurkyloo (from that thread, she maintains it and if you click on the links in the first post, it goes to pictures and information she's collected) mentioned. I just asked her about calling the Boardwalk Bakery.
So I'm deciding if I want to pick it up myself at the Boardwalk Bakery, or have in room dining deliver it, and for that I have to decide what kind of a cake I want, do I want to spend $100 on a fancy shmancy cake, or just get a basic cake and get a fancy shmancy bottle of wine!
IF you wanted a cake from Contemporary (the chefs there do amazing fancy fun cakes!) and didn't have a reservation, people have posted they have it delivered to the Wave restaurant
ETA> Here's the link to the list of resorts:
http://disneytravelbabble.com/how-to/order-cake/by-location/