Cupcake tower support?

I went through some of the older posts and didn't see a lot on cupcake towers....  I purchased carboard cake rounds (enough for 5 tiers with 8 inches being the smallest tier).  I have plans to paint (and seal) the cardboard, and put ribbon around the edges, but for the life of me I am stumped what to use between the tiers that will provide ample support but not take up too much room from the cupcakes on the tiers.....

Suggestions?