Successful cloud computing migrations

I'm looking for examples of开发者_JAVA百科 successful cloud computing migrations with any of these attributes:

• High traffic
• In depth explanation of what they did:
  • Did the go with an internal cloud, IaaS, PaaS, or some hybrid approach?
  • Did they have to rewrite any code?
  • Did they have to migrate data structures?
• How successful was the migration in terms of:
  • Time savings
  • Money savings
  • Added functionality or anything else?

If you know of anything interesting please share!

I just found a whole list based on Amazon Web Services here. There are also some PDF case studies for Eucalyptus (Yankee Group and Wells Fargo).