Hello Mr. Hotelling,
Glad you were able to sell your song, (Sniker)
Actually, I am glad you learned something from this. But my suggestion is this. I haven’t tried this myself, but what if you emailed your AAC song to someone who bought it from you. And you would of course delete if from your collection. Yes, its the honor system, but I guess you are an honest person.
When the recipient of the song gets it, he can add to his collection on iTunes, he won’t be able to play it on his computer, but he should still be able to import it into his/her iPod. Of course we are assuming this person has an iPod. Then this person should be able to play it.
Not a complete solution but still it might be good enough for some people.