This thought just occurred to me. Remember how Vivi is a prototype black mage, produced by Kuja? The mages in the Black Mage Village are also products of Kuja's evil plan. Now, the mages in the BMV are given numbers with which to identify themselves. Could it be that 'Vivi' is not in fact a name, but a number written in Roman numerals? If this were true the little mage we all love could be known as:
Black Mage No. 66,
Black Mage No. 5151,
Black Mage No. 516,
Black Mage No. 651, or
Black Mage No. 541.
What are your thoughts on this?