Arnie has a bunch of slides that he wants to digitize. Is there something that will take a carousel tray and one by one feed the slide and scan it? Leo says that would be an interesting product, for sure. Leo says he can do that, but taking them to a service like ScanCafe is a better option. Not only is his time worth something, but they'll take the time to clean them up and remove dust. If it's an issue of cost, remember that he'd be buying an apparatus and spending the time. In the end, he's probably paying just as much.
If he has the slide projector, then he could check out the SlideSnapPro.