hi guys. i've asked for this many times! in my job the time mounts up and i often use cubase built-in vari-audio even though it isn't as good as Melodyne, simply because clients want things fast... if you are tuning 6 or 8 tracks of backing vocals, cubase lets you open the clip, edit all quicker than it would take to trasnfer the stuff into Melodyne in real time.
here is a link to harmony plugin that also does pitch detection. they HAVE been able to set it up to analyse without having to be recorded in realtime. http://vielklang.zplane.de/
so if they can do it, it must be possible!
with this function i would use Melodyne for EVERY pitch edit. the realtime transfer is way past it's bedtime!