OK, this is a way outside of the box idea, but what if you mailed (FedExed?) a special code to the credit card billing address that the customer had to enter on your website to initiate the actual shipping? If the CC owner did not make the purchase they will either contact you or never enter the code. All orders where the code is not entered in 30 days are refunded to the cards. Obvious delays come from this, but you asked for ideas, even though this one's "out there".