I was wondering how to transport a cake that I cannot locate a box size big enough for ... All the cake boxes seem to be about 4 inches shorter than what I need..It's just a rectangle cake...

Can you do what the bakeries do...which is to staple the box into an open position, or is there not even enough room for that? I did that for my last cake and then taped plastic wrap over the opening just to keep the cake protected.