The result of a few hours of hacking:

pavucontrol cannot only control the volume of hardware devices of the Polypaudio sound server (http://0pointer.de/lennart/projects/polypaudio/) but also of all playback streams seperately, much like the new Windows Vista volume control application.

Get the Polypaudio Volume Control while it is hot (http://0pointer.de/lennart/projects/pavucontrol/).

On a side note I released updated versions of both the Polypaudio Volume Meter (http://0pointer.de/lennart/projects/pavumeter/) and the Polypaudio Manager (http://0pointer.de/lennart/projects/paman/) which are compatible with Polypaudio 0.8.