Prior to Cataclysm, Lord Sakrasis' Scepter was looted from Lord Sakrasis. The off-hand was de facto unobtainable since the rare mob's level was noticeably reduced. It has returned to the game through the garrison building, Salvage Yard (must be level 2+). See Contained In tab.
Of special note: Unlike most off-hand gear, the scepter will display on the character model even when sheathed. Also, the scepter has a unique appearance.