Interesting :) Why no "print-frame" attribute here? and then also probably the relative-x attribute could be added.

On a slightly related topic, I think we loose the ability to import/export the "offset" tag for chordnames that are not aligned with notes. http://www.musicxml.com/UserManuals/MusicXML/MusicXML.htm#EL-MusicXML-offset_1.htm Do you want to take a look or should I?