Re: standalone OSD
You need to look at the Kinetics documentation (it is available at the Seagate website). The Kinetics stuff actually implements an object store for the Ethernet attached drives, and will do HA and so forth on them. I don't know how easy it would be to make a Ceph cluster out of them (haven't spent much time looking at how Ceph uses drives).
I suspect that Ceph would be better served by the HGST version of this, called Open Ethernet Drive Architecture, which simply pushes a Linux distro down into the Ethernet-attached drive, where you can do whatever you want with it. So maybe each drive can become a member of the Ceph cluster...
Oh, and the drives that I've seen all have the standard SATA/SASA connector with Ethernet mapped to them, and implement the SAS-style multiple connections for the single connector.