Does anyone know of a similar setup that allows client-side encryption as well, with some nodes (those in the cloud) acting only as dumb storage that never sees

Does anyone know of a similar setup that allows client-side encryption as well, with some nodes (those in the cloud) acting only as dumb storage that never sees the encryption keys? The only thing I'm aware of is drbd, which acts at the block level, so you can stack dm-crypt and any file system (including OCFS2) on top. As far as I know, drbd only supports 2 nodes, though, which kind of limits the appeal. (I'm specifically not talking about tunneling a normal cluster file system via SSL, which only provides end-to-end encryption)