The "Suckless Init System" is a real init system and is derived from M. Farkas-Dyck's Strake init code. This "suckless" init system is designed to be a simple system and was made to scratch the itch of a developer wanting to remove BusyBox from his toy Linux distribution, Morpheus.
This init system is indeed very simple: "sinit exposes a set of operations via a FIFO. Normally this FIFO resides at '/var/run/sinit.fifo'. There are two commands currently supported, 'reboot' and 'poweroff'."
The Suckless Init System was shared with Debian developers but obviously isn't a serious contender in Debian's init system battle, but it's mentioned in case anyone is after a small Linux distribution project to checkout (Morpheus) or are looking for a very simple init system in comparison to systemd or Upstart. Sinit has been pushed to this Git repository under the MIT/X Consortium License.