I think if you dig around in the installer, you will see that it is modular, and you can do exactly that. There are certain modules that will need to come preconfigured, such as the users, base, permissions, groups, etc, but other than that, the installer is just reading the init file and installing. So what you are asking for, I do believe you already have.
grape -- You make valuable points about the users perspective on software. What I don't understand is when people turn software development into some sort of "moral" or "political" cause. I have bitten my tongue quite a bit on the envolution people, even though a couple of them have thrown enough stones at me to build Bedrock (WIIILLLLMMAAAA!!!). One of these days once I am out of the managing scene for CMS aps, I may write a book;)