Back in summer 2010 I did a proof of concept around Windows Azure & ADFS. The challenge was:
How can we deploy a departmental application in the cloud and have employees connecting on it using their corporate account?
Basically, how to project a corporate account in the cloud?
This was before Azure AppFabric Access Control. The solution had a web application using Active Directory Federation Services (ADFS) directly.
I did blog the experience of that POC over here: