Does anyone know any good tutorials or books which basically start you off by creating a partition, sticking a Linux kernel on there and then booting it to launch some random binary? Then incrementally adds to it until you have something like a full system?

Essentially I want to see how a Unixy system fits together from boot onwards. I know that init gets the system up and running then launches the login shell but I'd like to bypass this and have a look at building my own primitive replacements in interesting cases just to see how it all slots together.

I've ran through LFS but it tells you how to get things working without really touching on how it all works. It doesn't give you any insight into how the kernel decides what it is doing after boot up. How the init system actually works, etc.