At least both S3 and Cloud Files support a PUT copy operation that can copy a file from another object in the same or another container on the same service. Note that s3's requires a special set of API operations if it's large enough to require multipart.

It would be nice to support a copyFile operation.

I want to support temporarily hidden files in my system and it looks like – because while AWS supports per-object ACLs, Rackspace's CloudFiles permissions are per-container – to do that in a platform independent way I'll have to use a COPY operation instead.