Switching from one TTY to another kept resetting my scrollback. That is annoying. That is also hindering my "How long can I go without installing X11" challenge. I figured that if I was able to keep copies of the frame buffer contents and switch between them I might be able to keep the scrollback. So the logical conclusion is to try and write a kernel module to do just that.
Just run make in the src/ directory.
Included are also scripts to load and unload the module (MUST BE RUN AS ROOT).
You also need a copy of the Linux kernel headers.
The makefile assumes the module Kbuild scripts are installed in /lib/modules/[uname -r]/build so adjust if needed.