So, I was looking for a nice XML mode for Emacs and there it is!
Pointed out by Tom, a nice article on nXML, a XML mode for Emacs
that does (hold your breath!) RelaxNG. I need to try this out, as I’ve
been working on a RelaxNG schema for Archetypes TTW on the last few
days together with Godefroid Chapelle and we’ve been using <oxygen/>
on Paul’s Mac, but its not as cool as Emacs. Yay!