If you have the paper, flaunt it like Tesla (TSLA) CEO Elon Musk. That could be what other billionaires are about to do as they seek to drive headline-grabbing change at well-known public companies as Musk did with Twitter. "It's the beginning of a wave," Lawrence Elbaum, co-head of Vinson & Elkins' Shareholder Activism practice, said. "It's not the first time this has happened. There's lots of billionaires who have bid for companies in the past. There's lots of billionaire activists that have bid for companies." "I think we are going to see a lot more unsolicited bids on a...