Senator Moonbeam was for a watch face to commemorate John Glenn's return to space on the shuttle. All of my caricatures start out as a pencil drawing, then inked and scanned. I use the bitmap tracer in Xara and then remove all of the extra shapes that it makes.  I print the resized head, draw a body and then rescan and trace. The shuttle was completed in the same way and positioned to the back of the body.