DomainBop
Dormant VPSB Pathogen
Update: I got the storage box (BX-100, 100GB). It's most usable by sftp and scp, and you can mount it as sshfs though I've always heard sshfs has reliability problems (it works through sftp under the covers, I think).
I sftp'd a 1gb file to it from my Hetzner dedi and got 50MB/s transfer, pretty good. It supports up to 10 concurrent connections. You can change the BX size on the fly using the Hetzner robo console. I don't know how that is reflected in billing. They don't tell you which data center the server in, but I might open a ticket inquiring. It would be nice to have multiple BX's in separate DC's to have some spatial redundancy.
Overall this is not the cheapest storage out there, even at the 2+ TB level, and it's limited in flexibility (scp/sftp only, no rsync, no S3, etc). But I still think it's a good product, at least for users already hosting servers at Hetzner. It's fast, traffic over the Hetzner network is free, and (maybe this is wishful thinking) I feel a bit less worried (in terms of sudden deadpool etc.) about storing the data at Hetzner than at some of the lesser-known VPS companies.
The StorageBox line just became more attractive with the addition of free snapshots:
Starting now, you also have the ability to take snapshots of your Storage Box data. With these snapshots, you can then restore your system to previous states. Storage Box BX60, for example, allows you to have as many as 12 snapshots.