CakeAlexS
Well Melodyne can remove vocals from a track for instance, and R-Mix is supposed to do that.
I have used R-Mix often to remove vocals from final (commercial) recordings and it works very well for this purpose. Some songs have the lead vocals panned slightly, and R-Mix allows for visual adjustment of this.
One technique I have found that works well with this specific application is being as precise as possible... and this can often be achieved best by 2-3 successive iterations of R-Mix with smaller, overlapping target areas, rather than only one R-Mix instance with too large of a target area (that can deaden the "non-vocals" on you).