I'm brainstorming ideas for an upcoming competition cake, and I prefer to use cake dummies. I'm wondering if this design could work with styrofoam? Somehow I'm worried that there will be too many sharp edges and corners, and all of my fondant will just rip. I'm also concerned about cutting wedges out of the round dummies. I'm afraid I won't get them as even as if I were to use a real cake.

Any advice appreciated!
Here's the cake I'm referring to:

http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=919383

I made a duumy like that for a bridal fair last year and it worked well with a dummy. Even better, in fact. I let the separate parts dry thoroughly before I put it together which was nice because I could move the about with my hands to find the best positions.

You can round off your dummy edges a bit by rolling the sharp edges on the counter or table. Helps the fondant not tear!!

I wanted the sharp edge on mine so I covered the sides with a strip and the rolled out the white top part separately.