My parents own a beachfront house at the St. Regis Bahia Beach, and they're also Cent card holders (well, dad is), and have been Amex cardholders since the late 60's.

Dad was contacted by Amex about allowing his property to be rented by them. I'm not entirely sure of the terms, but it's enough that the mortgage, fees, and utilities are covered, while still retaining 50 days of use per year. So not bad.