I wanted to know if it was possible to hide certain audio devices from the volume widget (on desktop or on panel). I don't want to completely disable it, but I don't want it to show up on the desktop widget panel either. Maybe have a separate config and add a toggle option for devices you want to see, but that's my guess.
You can indeed do this, but you have to do it on the System Settings "Sound" page. For the device you want to hide, click the combobox next to its name and change the value to "Off". You can also use this to disable just part of it (i.e. if you have an external soundcard with just speakers plugged in, you can disable the microphone input there to make the useless mic device disappear).
I was thinking more of a separate view option, like the desktop widget can show different devices from the panel widget. I have my capture card and webcam connected to my pc, and I'm trying to keep it clean for my desktop widget. Let me know if this doesn't make sense.
Per-widget visibility is probably not in the cards, sorry.