Larch is a live CD construction kit for Arch Linux created in early 2006 by gradgrind (Michael Towers). Targetted at those who prefer the DIY approach, the aim is to produce an easily customizable custom installation/rescue CD that is more like a desktop environment than the stock Arch installation CD.
Full documentation is available on the project's website.
gradgrind's larch page - Official project website
Arch Linux Forums - The original Larch thread