I pre-ordered a Portenzo iPad 2 case last week and now they have updated the features for it. It now will sleep/wake the iPad just like the official apple smart cover. I can't wait for it to arrive.
http://shop.portenzo.com/ProductDetails.asp?ProductCode=Notebook-Style-iPad_2-case
http://shop.portenzo.com/ProductDetails.asp?ProductCode=Notebook-Style-iPad_2-case