The last major threshold of digital audio processing has been broken...
http://www.celemony.com/cms/index.php?id=dna&L=0 Celemony has effectively now completed the audio/MIDI bridge. The upcoming version of Melodyne (plugin v2) will contain Direct Note Access ("DNA"). This allows for true polyphonic editing of harmonics. You can literally change key signature of a piece AFTER recording it.
(MDSP actually had the first I'd ever seen of this technology years ago. Unfortunately, due to processing speeds and interface, it's taken until now to become viable.)