If you really want Delta miles and don't want to do any of the above great suggestions to build your AA balance, you could transfer them to Delta through your Diners Club account. If you don't have a Diner card - you could do the transfer through someone else's Diner's account. I could help you if you decide to do this.

However, you would loose 50% of the value - 15K AA miles-->7.5K DL miles. Not a good deal in my opinion. Better to get another 10K AA miles and use them for an award.