Most of our servers are DB anyways. We have 2 load balancers, 6 web servers, and ~40 DB servers.
Wow, that's not what I was expecting.
I have no idea if those 40 DBs are just mirrors sharing the load of some heavy queries or you are sharding the data in some way. If they are all just replicated maybe move most of them up into the cloud where they talk to your web app. But I don't know how much data you have to replicate up into the cloud or how long that would take.