I think AA/IB is more likely to go through than AA/BA. Barajas(MAD) is open to any airline, and I am not sure if it is slotted either.
Flying Isd, I think there really is a chance at that happening and I wouldn't doubt it either. American doesn't need to fly to every european destination, and they shouldn't have to.
I think Iberia and Finnair are the best picks for AA. AA is already partnered with Finnair, so they might expand that, and they should see if they can get immunity with Iberia. All of the airlines are in Oneworld.
Give me a break, I created this username when I was a kid...