There is a National Museum of Funeral History in Houston Texas, and they have a Rolls Royce hearse, and other cars

All from the Facebook page they have at https://www.facebook.com/pages/National-Museum-of-Funeral-History/108616709236095?id=108616709236095&sk=photos_stream

Seagrave Safety Sedan, restored by the Detroit fire dept volunteers, to be used as a fire dept hearse

I remember finding out about this a couple years ago, but was unable then to find anything out about it.
These images are found on http://www.flickr.com/photos/sjb4photos/8061362709/in/set-72157627006001214/