Three times in the past I have redeemed 35K BA miles for a free R/T coach on American Airlines between the mainland and Hawaii, I consider this to be ALMOST as good as getting an AAdvantage 35K award for only 17.5K miles (if I recall correctly the partner tickets weren't quite as flexible as AAdvantage awards - for example no stopovers were allowed when using BA miles for travel on AA if my memory is correct).