Agreed on the money. I'd be shocked if he doesn't re-sign with the Spurs, though.
As far as the length, I'd be surprised if he get's five. Five is rare and is generally reserved for foundational pieces. I don't think they'll care much about the fact that he could remain for a season past this current era, nor should they. He'll only be 31, probably making $6-7M (which is fine now and will only look better with where the cap is projected to be by then) and expiring, plus he'll be one of the most experienced, accomplished role players in the league. In other words, he shouldn't be difficult to move at all.