Note: this post is from 2007, outbound links may be broken.
Daniel Pompougnac releases Lierre
With Lierre you mix by using your mouse to activate or deactivate mixer channels.
In the top pink area all tracks are audible, but when you move your mouse over a pad of a specific track it will mute. In the bottom blue area all the tracks are muted, except those tracks where you move your mouse over the pad.