T. Boone Pickens is one of the great characters of American business.  At least he ought to be, given that matchlessly resonant name, so perfectly suited to his central-casting persona as the quintessential, plain-speaking independent Texas oilman.  But if his name harkens back to frontier times in the Wild West – and he first rose to prominence as founder of Mesa Petroleum way back in the 1960s, then won notoriety as a corporate raider (or, as he prefers, pioneering shareholder activist) in the 1980s – it’s also true that Pickens has made a late-life comeback in the 21st century.