Through a recent Call of Duty: ELITE update from the folks over at Beachhead Studios, some users have have been able to extract the complete list of Black Ops 2 League Emblems and Prestige Emblems, including the mysterious Prestige Master emblem.
As mentioned below, these additional Prestige emblems (last four at the bottom-right) are unconfirmed as additional Prestige levels.
Black Ops 2 Zombies emblems and additional Prestige emblems