$30 billion: A half-German college dropout, Batista has long said he wants nothing less than to be the world's richest person; Mukesh Ambani (India) - $27 billion: Mukesh, 53, dropped out of an MBA from Stanford University and joined Reliance in 1981; Christy Walton & family (USA) - $26.5 billion: Christy Walton is the widow of John Walton, who was the son of Wal