Has anyone tried having a tiered cake where only one tier is real cake?

A bride is asking me to make a 3 tiered cake; 12 inch dummy for the bottom tier, a 8 inch chocolate cake for the middle tier, so they have a ckae to cut and serve, and a 4 inch dummy for the top tier.

I wonder if the cake will look right.

I plan to cover in fondant and decorate with roses (real or sugared hasn't been decided yet)

If anyone has experience or suggestions I would appreciate it all.

Thanks in advance,

Gonetothedogs