Have you looked into the stress free support system? Peggy Does Cake told me about it and I love it. It is a metal plate system so basically all the weight is on the metal plates. It will definitely work for two tiers. I know use can use for three tiers but if you are concerned about the softness the middle tier may not be able to hold the top.
You could always also get a floating cake stand. So in essence the cakes are not stacked on each other.
