I believe this has got to be one of the hardest things to do photographically. And then you have to change your expectations. Remember, you are trying to give the viewer the feeling that they were at the concert (at least that's my goal) which means un-even lighting. You can't get away from that. Runmonty's right. That last one is the winner. You captured the feeling she was singing into the mic. Too bad Acadie-Libre is not around. He could give you a few tips, I'd bet.