It doesn’t, it only has very basic export options, to either MP3, AAC, or a ringtone or podcast which I think are m4a and m4r. At present I’m only using Garageband to see what information the midi-file contains, as Garageband can’t even export a midi file.
I have read that WAV files can be more than 2 tracks, so will try exporting the .mid file from Quicktime as a .wav and see what information it keeps.
Any other suggestions welcome.