Any chance of getting a stereo polyphonic pitch shifting algorhythm?
Check out the way the electro-harmonix pitch fork tracks.
One of my colleagues had talked up the idea of doing an algorithm like that in the past, although I don't think he had the electro-harmonix pitch fork in mind when he was describing it. It certainly would be useful, although what people have been requesting more often have been a Univibe algorithm or another multi-FX along the lines of SpaceTime.
I think there were some forum posts in the past where people were asking for polyphonic pitch detection, but that's not actually what's needed to implement something like the pitch fork.