If 19 walking dogs isn't your style, what about a single walking dog? According to
this, a Chinese guy has trained his dog to walk up to five miles. Of course, since the weasel words "up to" include the distance "5 feet", I suppose one could take this with a grain of salt.
More importantly, since my own dog now faces arthritis in his rear hips and knees, I would encourage everyone NOT to do this with your dog. Just walk it normally, please.