Thank you, Starwood Lurker (post 766 above)!
I emailed via the "secure message center" on Wed. My sign-up 30,000 point bonus posted today. This is 14 weeks since my spend passed the $1000 threshold!
I gather from my fellow posters that the delay in my case is not at all unusual. AMEX has the strategy in place to require a 3 statement waiting period before posting these Starwood chargecard sign up bonuses.
How about a new ad campaign to promote the Starwood AMEX card: Sign up for our Starwood American Express card and wait longer for your enrollment bonus than for any other chargecard! Sign up today, use the card, see your charges post to your account the same day, then mark your calendar to beg for your missing sign-up bonus in 4 months!