I've not reached it for myself, but a new Grandmaster area in the Mousehunt game has been found. This is what I've found off the discussion boards. Shadow type traps used.
I checked my trap and found that I had caught a mouse! I caught a 5 oz. Lycan mouse from the Mousoleum worth 9,246 points and 5,505 gold. Additionally the mouse dropped the following loot: Shredded Furoma Map Piece. My weapon seemed especially effective against this adversary.