Can Panels be nested?
 

I'm creating a LOT of panels for my current project, and I'd like to be able to better organize them if possible. Can I create "parent" panels that, if selected, will display a second set of "child" panels that the user would interact with normally? Basically I'm looking for the same behavior that the Editor tabs do when you assign them a "group" attribute.

I'd like to know this as well. :)

No, this isn't an option.