In a 17g, if you really want cleaners, Ottos would be the only things you could get, and they perfer to be in schools of a least 5 and alot of plants so that really wont work either. All pleco will get to big for a 17g.
Why do you want a pleco? If it for algae then I would say not to get one. They are NOT great cleaners, and have a large bio-load. You could get some snails or shrimp to help cleanup.