Are you just basically looking to create a distributed file system to be able to scale for large data? There's MogileFS, but you could also easily code one up to suit your needs.
Unless you wanted something specific in terms of a "cloud"...
Loading user information from Channel 9
Something went wrong getting user information from Channel 9
Loading user information from MSDN
Something went wrong getting user information from MSDN
Loading Visual Studio Achievements
Something went wrong getting the Visual Studio Achievements