Sound Control class?

I’m wondering whether there is a good Sound Control class out there that extends the functionality of Flash’s basic Sound classes? I’m about to write this class myself, but I’d rather not reinvent the wheel if something already exists.

Basic functionality I would be interested in:

Automatic checks to make sure the user can support sounds. Sound objects are currently null when the user does not have a sound card. This can cause exceptions.

Fading out sounds over a short period of time, rather than ending abruptly on stop.

Checking to see whether a sound is already playing before playing it a second time.

Organizing sounds into groups (eg: background music, sfx) so that I can control a group of sounds independently, adjusting volume, etc.