I value them at close to about 1.5-3cpm. I know I get more redemption out of them since I use them for international F travel, but like others have said, you can't really take the F fare and divide by the mileage redemption cost as I certainly would never pay $20k to fly in F. This is why my number is sort of vague, because I'm not sure of all my costs.

In case you didn't know, the reason why Science Goy made the "opportunity" ominous is that AA doesn't like it when private parties "trade" miles.