Are there chin implants that will only add vertical length without adding width? (photos)

There are muscles at the bottom of the chin that prevent make it extremely difficult to add vertical length to your chin. In addition, they will make your chin appear wider. The best treatment for vertical lengthening is a genioplastry. It will provide you with the most natural results. 

For isolated vertical chin lengthening, or with some horizontal augmentation as well, you have two options. Chin implants do exist that can add just vertical lengthening but they have to be custom made for your face to do so. No such standard vertical lengthening chin implants exist that do not also add width. The second option would be a vertically lengthening bony genioplasty which always make the chin a bit more narrow as well.