Automatically Changing Sound Preferences in OSX with USB insertion

Seems simple enough:  when we insert a USB device, or ideally when a Bluetooth device is paired and lit up, I'd like the customer's Mac OS/X box to jigger the sound prefs to fit the pre-configured settings for the new device, and set it as the output device automatically.  So, when we light up a headset, skype and wow and all that will just work the way it should.

I'm thinking there's gotta be a HAL-like dealy for Macs, and that we can hook in a script in there.  That's what I'm thinking.  There's a potential script we can run here, but the trick is finding out how/where the subsystem lives.  Until then, we could be stuck with cruder, user-diddled tools like

• SoundSource at Rogue Amoeba
• Change audio devices via shell script at who's hacks 

Here's hoping we can make it more automated.  It seems Apple machines should do this, if you believe the hype.  Me, I don't have nearly enough/any Mac OS/X experience.