You can find here https://github.com/Obarun/rootfs-obarun/tree/master somes scripts to build a rootfs. This repository is made for learn how to kernel boot and how to build a rootfs. This scripts are similar as arch hook but more simplicity. Those scripts are constantly developped, so it isn't for production environment.
You can post here your comment, observation, answer, critizism here, don't hesitate :)