Don't believe so, unless one uses scripting. (I'm not a propellerhead on that matter, though.) You could, of course, resize all the contents within an artboard at once by selecting them in the Layers panel.
Here's the best way I've found to do it.
With the content now scaled, you can either duplicate that Artboard back to the original document, or use it as its own new document.
Hope that helps!
Try this: Using the Image Size command on the entire doc scales all artboards and content to the new size. Figure out the new size as a percentage and you're good to go.