I threw a NAS in a friends house that is configured to bootup and reverse ssh tunnel to my rack where it then accepts scheduled encrypted duplicity backups.

I do not even need to trust my friend as duplicity encrypts all data against a yubikey held pgp keychain before it leaves.

The backup NAS could phone home from anywhere with internet access.

This is very slick. Apparently, I need to make some techie friends. Tarsnap is pretty affordable for off-site backups though!

the friend doesn't need to be techy just have a house

Well, a house and some kind of NAS or at least a computer that is always on. But I take your point. This idea is brilliant though!!

I expect one buys the NAS themselves and pay electricity