I have gushed over Mike Maihack's Supergirl/Batgirl art in the past on this blog. Maihack seems to be able to capture the optimism and enthusiasm of Supergirl in his wonderfully cute comic strips and pictures.
If I was at the convention's art auction, I think I would be bidding pretty fiercely for this piece.
The auction is at the end of the convention day so anyone going should make sure to try to hit the auction or at the very least thank Maihack for his work (both here and on Cleopatra in Space).
Here is a link for the convention itself for anyone in the NC area still on the fence about going: http://www.heroesonline.com/heroescon/ I love that Supergirl is the character on the convention logo. In some ways I am glad I am not attending. There are so many creators I would want to meet and get art from I would probably mentally overload and go catatonic!