i once sat down to go through this as a challenge, but started to get bored quickly. skipping ahead, i built bash, configured grub to init=/bin/bash, threw in coreutils, and was very thrilled to see my very own "distro" boot in under a second (not counting bios init ofcourse) on an ancient p3 box.

i think i disabled everything i could think of in the kernel (including filesystem support, which was quickly rectified) for a truly 'minimalist' experience.

it ofcourse didnt do much but it was very responsive.