Now in a business context this means expensing a business-class connection into your personal household (or a director-level person's), and having a small computer there with a something that's running redundant drives.
The only "untrusted" piece is the network itself (so, use SSH). A nightly Rsync should do. Place it in a house of someone who is already responsible for that data's security and you have no conflict of interest. Disk encryption avoids damages from a home break-in theft.