I take it you're referring to the steelbook found in the CE below?
http://collectorsedition.org/game-db...tion-ps3-brd-1
I don't consider it to be that valuable or rare but it doesn't come up that often I think. I don't really look for it though as I already have it
If you're after the steel, might I suggest this listing?
http://www.ebay.com/itm/Smack-Down-v...item53f2c41554