I know that this is probably just a pipe dream... It'd be great if mpt could export to lilypond (or similar) format for notation... This would require a whole lot of extra information to be stored with each track (like groupings, clef, key signature (and changes!), time signature (and changes!), etc.).
I know that it would be virtually impossible to produce wonderful-looking scores with just the click of a button, but you could at least get something out... I think that this would be a lot easier than exporting to say, midi, and a lot more useful. And lilypond makes really quite pretty scores. =)
Reference: http://lilypond.org/