At least fairly simple to get down to 3GB
When doing purging operations, I have found it to be fairly safe to do the purging without persistence, then remaster and test, and continue with the next step also without persistence. The occasional packages to install during the process, don't need persistent store.
Here is a fairly simple and safe way to get down to ca 3 GB: Drop games, science, education, tex and kde, plus a few other packages.
The image produced by squashfs compression is ca 150MB smaller than simple cloop compression in this case, so there may be a case for a squashfs version of minirt.gz here.
I don't think it should be impossible to get down towards 2GB, but the more we purge, the greater the risk for a crash. (And I don't think we should hope for doing better than Klaus Knopper himself :-) )
This will give a few hundred MB for user data. Question for the OP: How much is needed?
Code:
sudo apt-get update
# Groups
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep ^games | cut -d' ' -f2`
sudo aptitude purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep ^science | cut -d' ' -f2`
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep ^education | cut -d' ' -f2`
sudo aptitude purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep '^tex ' | cut -d' ' -f2`
sudo aptitude purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep '^kde' | cut -d' ' -f2`
# Single or small sets of packages
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep eclipse | cut -d' ' -f2`
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep inkscape | cut -d' ' -f2`
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep scilab | cut -d' ' -f2`
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep scribus | cut -d' ' -f2`
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep pidgin | cut -d' ' -f2`
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep denemo | cut -d' ' -f2`
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep amarok | cut -d' ' -f2`
sudo aptitude -y purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep chromium | cut -d' ' -f2`
sudo aptitude purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep phpmyadmin | cut -d' ' -f2`
sudo aptitude purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep mysql | cut -d' ' -f2`
sudo aptitude purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep gnumeric | cut -d' ' -f2`
sudo aptitude purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep help-de | cut -d' ' -f2`
sudo aptitude purge `dpkg-query -W --showformat='${Section} ${Package}\n' | grep ' vim' | cut -d' ' -f2`
sudo aptitude -y purge `deborphan`