Can an 11X15 in cake be constructed with 3 layers cake and 2 layers filling? Perhaps if I freeze and then fill and then freeze again it would work? Filling is SMBC. Im afraid it would be unstable, but if I keep it 4 in tall or less Im thinking it would be ok. Could I freeze it a week early? Thanks for any input!

Well I am doing something similar right now. What I have been doing is baking, removing from pan and then filling, then I froze it. After I did the 5 layers (I'm going to attempt carving an aircraft carrier cake from this). However, I"m using plain old buttercream and not SMBC so I don't know if that will make a difference or not. I've frozen cakes with SMBC and they came out okay. Sorry if this is convulted, HTH.
terri

It's no different than stacking and filling 3 layers of a round cake. The bottom tier of this cake is 3 18 inch round layers stacked and filled, and the next tier is 3 14 inch layers stacked and filled.
http://www.cakecentral.com/cake-photo_1071353.html

Jibbies