There was talk early on of a girl in arizona, and another near San Luis Obispo. I don't think anything came of either of those.
Pinz
I just found the link on the internet - there is a college student from 7 years ago still missing. Scott was sent a letter asking him what he knew of her as he was one of 100 students who had had contact with the Smart girl who is missing still today. A student who was with her last is the prime suspect but he has not been arrested. Yet now that we know Scott killed his wife and had something to do with the other girl at college it is time, I think, to look into him as a suspect and at least interview him about the missing Smart girl to see if he had anything to do with it?