>>834156 (OP)
>what does it take?
Patience and your own servers, if we're talking about a real distro with userbase, forum, devs, packagers and so on.
>>834176
>software preinstalled, preconfigured
This OTOH is pretty easy. Take an existing LiveCD image, extract it, mount its filesystem, use chroot and edit the config files in /etc then make an ISO out of it using mkisofs or similar. I admit I haven't done this in a while so it's probably even easier to do nowadays with new tools.