During my play through in normal I came across a black smithing plan for an item called "staff of herding". There's nothing special about this item, it's a normal white item with around 3 dps on it, but for some reason the mats required to make it cost an obscene amount of money (wirts bell being one of them, I found it in a vendor in act 2 for 100,000 gold).
This makes me fairly certain that the completed staff has something to do with a new secret cow level! This is all speculation, as I'm no where near close enough to being able to afford the items required to make the staff, and I don't know if you need to do anything after you make the staff. I'm also not sure if this has been discusse before or previously discovered, as I didn't do too much reading into the items of the game before playing
http://diablonut.incgamers.com/item/staff-of-herding2
That should be a link to the item I'm talking about