I just came across this, if anyone's interested. It's a free vocal doubler plugin from Izotope. I've not tried it so don't know how good it is, but I've included links below to some demonstration videos.
https://www.izotope.com/en/products/mix ... ubler.html
https://www.youtube.com/watch?v=cOYW2RXtWhM
https://www.youtube.com/watch?v=3DjksvRKgD0
https://www.youtube.com/watch?v=2QtnwdHRnVc
Vocal Doubler
Moderators: Acoustica Eric, rsaintjohn
Re: Vocal Doubler
I grabbed this awhile back; izotope makes good stuff!