Ok, I think I found a possible solution involving tape.

http://arkeia.com/downloadfree.html

This is a site that offers a backup program, and for free, you can get the server software for Linux, and 2 free type 2 client licenses. And Linux ARM happens to be one of the type 2 clients. So, in theory, this client could be installed, and from the server, complete or incremental backups could be done across ethernet.

I'll try it once I have my empeg later this month, since I already use the server on my network here at home.