There is a new auction site called TradingCardAuctions.com that deals exclusively with any kind of trading cards (promo, autographs, sketch cards, etc.) I have been trying to help promote the site and have listed one of my Iron Man 2 Artist Proof Card for it. The Iron Man 2 Artist Proof card features 5 members of the Avengers (Iron Man, Captain America, Thor, Giant Man, and Wasp) This is not a print or reproduction art but is an original one-of-a-kind hand-drawn sketch card. You can see the card above. Below is the web address to it. Sorry, I can't figure out how to make a link work here.
http://tradingcardauctions.com/auction_details.php?name=Marvel-Sketch-card-Iron-Man2-Artist-Proof-card-by-artist-Lak-Lim&auction_id=132777