Going through Linux From Scratch[1] manually and reading each component, while allowing yourself the time to look into interesting bits of each, is essentially this. I did it back in the early 2000's, and view it as one of the most useful educations I've ever gotten on how a Unix-like system functions (even if a lot of the knowledge is somewhat obsoleted now for many Linux distros with the introduction of systemd). I was doing it as research for how to ship a custom distro for a small purpose-built device, and while that never panned out, I've never once regretted spending the time to go through the process.

1: http://www.linuxfromscratch.org/