Another one here. My first real IT job was building a LFS based distro in 2005. :) It was fun. Though I was coming in with a year of Slackware experience already, so following some commands and dealing with build issues was not a new thing to me.
So I at least based it on m4 generated shell based build system scripts and my slackware package manager I wrote at that time. https://spkg.megous.com/