custom live cd

 sudo apt-get install uck


dowload ubuntu mini remix
 http://www.ubuntu-mini-remix.org/



 sudo uck-remaster-unpack-iso Downloads/ubuntu-mini-remix-14.04.1-amd64.iso


sudo uck-remaster-unpack-rootfs
sudo uck-remaster-chroot-rootfs


add universe and multiverse to the /etc/apt/sources.list

deb http://archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse

[apt-get upgrade]

...customize by apt gets ...
you can use apt-get install --no-install-recommends emacs

remove unused kernels by
 dpkg --list | grep linux-image
 sudo apt-get purge <unused ones>




sudo uck-remaster-pack-rootfs
sudo uck-remaster-pack-iso test.iso


for changing the default thema change
 /usr/share/glib-2.0/schemas/org.gnome.desktop.interface.gschema.xml
then

sudo glib-compile-schemas /usr/share/glib-2.0/schemas/

  /usr/share/glib-2.0/schemas/

sources:
 https://code.google.com/p/ardesia/wiki/Create_a_live_distro
https://lists.ubuntu.com/archives/foundations-bugs/2014-August/207632.html
 http://askubuntu.com/questions/65900/how-can-i-change-default-settings-for-new-users