Actually, if you're willing here's a suggestion, Shafted. I was planning on doing this on my own, but am afraid I don't have that much time.
Here's the deal:
Make an online alphabetical index of each and every xml tag (skin and menu) that MXM uses. I was thinking an HTML format so it can be updated instantly if need be. Clicking on a tag brings you to a description of the tag, the parent and/or children of the tag, and an example of the tag in use. If you've done any Visual Studio programming.. think MSDN format.
Sometimes, when I'm bored, I go through an index like that and read what every little command or tag does. It's a great way to find new features, etc. I learned Unix that way. Maybe it can be a good reference to MXM users.