How to make a remixed live CD

I recently discoved Debian live install images (https://www.debian.org/CD/live/) with Xfce. I want to make something similar but based on Trisquel GNU/Linux, which currently does not have an Xfce4 based image. So when I wanted to install Trisquel GNU/Linux I always used the netinstaller and then ran "apt-get install xfce4 lightdm".