Or perhaps easier...
If you want to make a modification in what's on a live-cd of Mint or one of the other distributions, the best place to start is with the methods that the distribution presents you. Mint has a function called "mintconstructor"
For other linux live-cds, try to google with that distro and the term "remaster". You can assemble your own, but it may not be that easy. It is not a co-incidence that there are so many variants of linux starting with Ubuntu.
I use openSUSE.