Andrea's great photos and the posts about them and Lartigue's car shot have prompted me to hunt for the book that describes the focal plane distortion: "...in the photograph by J-H Lartigue, the impression of speed is conveyed by the apparent forward lean of the car's wheel and the backward lean of the spectators. Both effects are due to the shutter, a fast-moving slit that moves vertically across the film, exposing different parts of it at different instants in time. Thus, in taking a picture of a fast-moving car, the bottom of the wheel will be photographed at one point, but when the slit in the shutter reaches the top of the wheel, the whole car will have moved to the right, so that the wheel comes out looking egg-shaped. In taking this picture Lartigue had to move his camera to keep pace with the car's movement. This, in turn, gave the spectators their odd appearance, for when the shutter's slit passed across their legs the camera was in one position, but by the time it exposed their heads the camera and film had moved to the right." [from "The Camera"; Time-Life Books; 1970]
Here are a couple of time exposures I took at Shibuya Crossing in Tokyo this past May with a Nikon F2.
[Sorry, image deleted during forum software upgrade. Please re-upload if so inclined.]