Is Webmin supported on Ubuntu 12.10?
I saw this old article that said it isnt due to Webmin not being compatible with the way that Ubuntu packages handle configuration files: https://help.ubuntu.com/community/WebMin
Is this still the case?
It was never the case (at least, as you're interpreting it). That post refers to the old Debian/Ubuntu packages of Webmin, and has no relation to the package provided by Webmin.com (other than both being a way to install Webmin on a Debian/Ubuntu system). The two were packaged by different people and in very different ways. Webmin itself is compatible with Ubuntu 12.10, and works with configuration files in the manner documented by Ubuntu/Debian. Unfortunately, that post doesn't make it very clear that it is about a specific packaged version of Webmin, and not Webmin itself
Ubuntu 12.10 is supported by Webmin.