A Cloud of My Own...

[JimmyNeutron]

Just build a computer, add encryption, and rsync the data from drive A to drive B.  Done!  If you need HDMI output, just install the drivers.

I'm doing this with my Intel Atom motherboard and two 2TB disk.  No need for fancy stuff because if I ever have to remount the disk on another system, I don't have to worry about compatibility issues due to the NAS using some proprietary software or RAID.