UPDATE: Completed. Works pretty ok for now.
I stumbled upon this cool extension called infolister. It lists your currently installed extensions , themes and whatnot. The idea is to periodically upload an .xml file to the server (the infolister extension already does this) and then parse that with PHP. Seems its much easier to do in PHP5 than 4 which is what my host is using.. argh. There is a test page (taken down – completed) for now, which I scrambled together that just does a simple burp of the file output as text without an special formatting.
Diary