Thanks for kind words!
As you already know all Fedora versions up to 14 are now EOL. These versions will not receive any new updates. This means that the systems may have security issue and so on.
There is no plan to add support for older versions. This is a technical issue as well as a security issue what I described above. Fedora changed over the years and supporting something it is EOL doesn't make sense for us. You are free of course to create your own plugin or extend fedora-os-plugin, but we will not include it in the base distribution. Sorry for that.
You can take a look at Oz if you want build older Fedoras.
I'm aware of the security issues. I've hand applied security patches to these machines over the years, so I'm not concerned about that. I'll probably have a go at creating my own boxgrinder os plugins. It will give me a reason to try out ruby, after using python exclusively for years.
And thanks for the pointers to Oz. If creating my own plugin fails, I'll look there.