I've seen several cakes where between the tiers the artist will use wine glasses, a vase, a candle stick etc.
How do you support that piece so that the weight of the above cakes doesn't push it into the cake. AND so that when the bride and groom go to cut the cake, the whole thing doesn't shift and tip over?
I've thought about hiding an SPS plate under the piece but honestly... I'd love to have a "clean" cake top. Just not sure...
Here are a few photos of what I'm referring to.
The first two pics look like cake stands so the part that is supporting the top is the same size as the top tier. You would have to have either several dowels or a large dowel in the center that would go threw the entire cake to hold the weight of it all. Then I would secure the plate that will be holding the top tier with hot glue or melted chocolate so that it doesnt shift. I would use the glue myself so that it was more sturdy, but make sure you have any strings cleaned up so its not getting on the actual cake.
The first cake and the last cake have the instructions on how it was done in the comment sections.