One other Flyertalker contacted me about this as well, and I've been looking into it on their behalf. This was American Express' response to that member:
"Unfortunately, American Express is unable to recover the unique ID associated with your account in this campaign at this time as this campaign was run in November of 2006. However, American Express will be running additional promotions in the near future so please continue to watch your mailbox for other special offers from the Starwood Preferred Guest Credit Card from American Express."
So, it looks like asking SPG to intervene is going to be a non-starter.
Sincerely,
William R. Sanders
Customer Service Coordinator
Starwood Preferred Services
[email protected]