OMG Lulu, I just had a vision of the future of what it will be like with my eldest DD - she already has that total lack of emotion when it comes to cutting things out in the hope of making her actually DO something to help and she's only 6! Anyway I digress.

Maybe you could go to spotlight and get a really nasty pattern for a dress - leg 'o mutton sleeves and all and threaten to sew one yourself (and I know you don't sew so the result should be good ) and tell her it that or nothing because you don't think she would appreciate a truly amazing dress - because by the sound of it she does deserve diddly squat for her formal.

Seriously though, if she is fine at her fathers place then shes obviously doing what she does at your place just to push you as far as she can so you snap and then YOU"RE the cow kwim? Is this something you can get her father in on at all? make her do more over at his place or something? (which I know doesn't help you out at all )