I have now reached the point with AA (Dublin office) regarding my DONE4 ex-IST that they have quoted the right price for me (allthough they first thought wrongly that my ITN was a 5 continent one, which it is not) and said that their airport ticket counter in IST can issue it. It's not clear yet if they can send the tickets by a courier nor have I got an answer is their ticket counter open also on weekends, which would make my day.

So it seems there is also a chance to issue ex-IST xONEs with AA, I will keep you posted as things hopefully progress within couple of days.