Used this to create my own custom Linux build http://susestudio.com/ Gotta say, it's pretty damn neat. I don't have time to learn how to build one from scratch and modifying other builds may take time. At least you can customize certain areas and have that image created for your use.
I am planning on creating a Red Eclipse version where the game is already included, plus desktop background, etc... for a light install but great to use for gaming for those who use *nix.
This may not be useful for some but I am typing this right from my own build with my own choices in the OS so yeah, it's at least fun to do.