Originally Posted by Efrem

Not a direct answer to your question, but close: Starwood has bonuses for getting their affiliated American Express credit card. That applies even though you're already in their program. Having it also gives you a two-stay, five-night head start toward elite status.

If you know someone who has SPG AmEx, they often have an offer where they can get a bonus for referring you and you still get the bonus for signing up.