Currently there are 48 native Wideangle Prime lenses for Canon 1Ds MIII and 24 of these lenses are autofocus (AF) type.
Canon 1Ds MIII doesn't have a sensor based image stabilization system but 4 of these Wideangle Prime lenses features optical image stabilization.
Since Canon 1Ds MIII has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 12 Wideangle Prime lenses with Weather Sealings.