Obviously your goal is to boot into a window manager without using any swap. Strip down the system, don't run hotplug, syslog, mail, etc. Turn of all the getty's except the one on tty1. Substitue bash with csh or z. Don't load any extension in the xorg.conf. Use fvwm or flux. Use kernel 2.4. It's has a smaller footprint than 2.6.
Basically really strip it down to nothing but a bare kernel and a bare X w/ a bare fvwm or fluxbox.