The best thing I can think of is to create something using a program such as Kid Pix Companion's slide show program.

If you use Kid Pix, simply use the magnifier tool of the electric mixer to blow up the pumpkin stamp and use it as a template for your pumpkin's face. You can keep it bitmappy or can smooth it out with the wacky pencil.

If you don't have Kid Pix, there are probably other programs that can do the same thing. I'd be willing to bet PowerPoint would be capable of doing something, although I'm not really sure about the older versions.