Attached is a style plugin for tabs. Now that Vertical Tabs is in Drupal core, I think it makes sense to have a "tabs" display style in panels core.
One item needs work: I couldn't seem to find the right Pane title variable to grab for the tab text. I am forcing it to lookup the "Overridden title" for now. Thoughts on how to do this properly?
Also: field_group module provides a wonderful 'horizontal_tabs' style based on the same structure of a vertical tab. With one line of code, I can detect the module exists and add "horizontal" to the options.
Merlin, I know you are against things like this generally, but since its so small I was hoping we could let it in.