It would seem that Google's Storage API, positioned right in Amazon S3's market, is geared to be their bulk cloud storage option. Though they do have the gsutil you mentioned earlier, the online Storage Manager works really well as a drag and drop interface for uploading/organizing files and managing "buckets".
(source: googleapis.com)
They also claim that because of their RESTful API, it's compatible with existing cloud tools:
Google Storage is interoperable with a large number of cloud storage tools and libraries that work with services such as Amazon Simple Storage Service (Amazon S3) and Eucalyptus Systems, Inc.
I haven't had a chance to test that yet.
You are permitted to create buckets (and cannot nest them) but you can name your objects inside of them with / to emulate your local storage:
By using slashes in an object name, you can make objects appear as though they're stored in a hierarchical structure. For example, you could name one object /europe/france/paris.jpg and another object /europe/france/cannes.jpg.
Google has planned pricing at
Storage—$0.17/gigabyte/month
plus other bandwidth costs.
Marked community wiki, since it's somewhat tangential, speculative, and not available yet.
