Okay, not exactly "in-camera" but it was a new approach that I thought was pretty clever.
Cinematographer Ray Schlogel recently Directed/Shot/Edited a music video with a different approach to the Pleasantville effect. He lit the set with green gels, keeping them off the subject. Then shot it with a Canon HD w/ 35mm lens adapter. To get the effect, he just desaturated the green out of the shot (using Sony Vegas). No roto.