there is really no such thing as "renting points." as a nonowner, you cannot contact MS and the points themselves would be useless to you.
what you are actually doing is renting a reservation made by a DVC owner. as a result, you can book 4 nights with one owner and then book another reservation with a different owner for the following 3 nights. but you do risk having to re-check-in and possibly move to a different room when the new reservation starts, so it's not ideal...