Is there any way to uniformly expand the Artboard from the center of the artboard? I like the way my current page is setup, but I just need more border all the way around.
The Artboard tool doesn't do it when holding Alt which is a shame but you can enter the dimensions for the W and H in the control par. To make it more interactive, click in the W or H field then hold Shift and press the up or down arrows on your keyboard, without Shift the resize will be slower in smaller increments.
Mark made a small script to pad an artboard,
http://forums.adobe.com/thread/287731
and here's another script to resize all artboards at once
North America
Europe, Middle East and Africa
Asia Pacific