Can't this just be some sort of frontend for making and distributing Ansible playbooks or some other configuration management thing. It's a lot easier to make it cross-platform, too, because there are loads of pre-made modules for dealing with package managers and OS-specific quirks. Like openbsd_pkg, apt, yum, pkgng and other modules (for Ansible, I don't really have much experience with Puppet, Chef or others) that let you ensure packages are installed before installing configs or whatever.

Ansible is also written in Python and has a very easy to use and useful API.

It could be overkill, though, the same things could conceivably be done with a shell script running uname and a massive "case $(uname) in OpenBSD) .... Debian) .... FreeBSD) ...." with a list of all of the operating systems.