swift is the object storage of Openstack. Think S3, but fully open source. As it's backed by rackspace.com, NASA, Dell and several other major players, adoption rates will explode.
I can provide a test account soonish if need be, else rackspace.com if offering swift storage. Their API gateway lives at https://auth.api.rackspacecloud.com/v1.0
Swift is supported by https://github.com/DanielDent/git-annex-remote-rclone