My mom did a neat one a few years ago. It was a colection of little pumpkins hollowed out to form bowls. All the little bowls were put on a big tray with the various vegetables in them. The one in the center held the dip and had the little pumpkin top lid for it.

She had them lined with plastic wrap so the pumpkin flavor didn't get into the vegetables. I don't know if you really need to do that.