As Jack-o-lanters demonstrate, there is so much you can do with one vegetable. One form of extreme pumpkin carving can be seen in these sculptural pieces from my friends at Extreme Pumpkins. The images in the gallery illustrate pumpkin carving with props.
I think the territorial pumpkin is really funny. I also suggest you take a second look at the rather crazy pumpkin fan who painted her baby belly to look like a jack o lantern. In this instance, her baby bump was used as the supporting prop!
Finally, the pumpkin self-portrait is absolutely brilliant. I love it almost as much as the squash on a spit which being burnt alive by nasty pumpkins.