[mjn]

Joyent has one as well (not OpenStack-based), with an interesting "integrated compute" option where you can send code to run over stored objects without spinning up an explicit compute instance: http://www.joyent.com/products/manta

I don't think DO offers any kind of a-la-carte cloud storage, though.

[nl]

OpenStack is working on a "send the code to the data" thing too. That's what Rackspace bought ZeroVM for.

If you want to try very alpha code you can kinda get it working yourself now (I think - based on mailing list discussion anyway)