You can search for EY space on the EY website under the Etihad Guest tab. If you see space under "Guest Business" that space is accessible to AA. You'll then need to call AA to book it over the phone. Ignore the pricing listed under Guest Business - that's just for using Etihad miles, the AA price is 70k for US - Middle East in J.

At the moment I don't see anything on SFO - AUH but I do see space on LAX - AUH and you *may* be able to add an AA leg SFO - LAX on the award if there is AA saver Y or saver J space.

You could also look into Qatar but they don't have an SFO flight so you'd need to find space on their LAX - DOH route on the BA website and then try and tack on the LAX - SFO space using AA Y or J saver space if available.

Just did a bit of searching and you should be able to do the following for 70k AA if you call in:

SFO - DFW (AA domestic F)
DFW - DOH (QR J, 777 - QR flight #730 )

Available dates: August 22nd, August 29th (though first leg is SJC - DFW not SFO - DFW). Since it's AA F to QR J you'll get the full AA F baggage allowance and then you'll just need to figure out DOH - MAD and can use UA miles (transferred from UA) for that.

If you wanted even more fun you could tack on a connecting leg from DOH - somewhere in Africa for an extra 5k or from DOH - India Subcontinent for no extra cost and then start your UA award from that point to MAD. Of course this works out to quite a bit more than the AA redemption on BA with fuel surcharges but it would much more of an adventure!