Most airlines limit FF mileage purchases to approx. 50k per year. Amex limits Membership Rewards point sales to 500k/year, so that would be a more reasonable option (2 seperate purchases with Amex) - however Amex charges a huge premium ($0.025/point) if making this transaction directly with them. This is why I've posted here looking for leads/info on a direct purchase from another source (private person or mileage broker).