This is nice and all, but isn't practical for anybody on linux (Paperbak used to be windows only, and the linux version you can find is very subpar).

I have found that splitting the key in 256 bytes chunks, then QrCoding them is sufficient for my usage:

https://gist.github.com/Gui13/5e5fe0c7c67d55373767d4965b1638...

With that script, a 2048 bits key in PEM is about 4 pages (+ 5 others if I print it in text format), which I can store in a safe, and conveniently rescan using zbarcam anytime.