A non-cloud off-site backup appliance. This is what I want (I know there are alternatives, but this is what I want): A device that I buy, and can plug at least one hard drive in to. I give it some sort of passphrase. I then place it in a friend's house and connect it to their internet connection. I can then access it remotely from my house. I can easily backup my stuff to it. My backups are encrypted, both over the w…
In that case, you can buy a NAS for you, have them buy one for them, backup stuff on your own NAS and let the replication from your NAS to their NAS happen in the background.
Bonus: backups/restore/browsing are much faster, and you can more easily accommodate multiple people wanting to backup at the same place -- instead of one device at your place for each of your friend, it's only one at your place to which all your friend's NAS backup to.
I use Synology NAS, not with this setup, but I know they have the software to do exactly this.