* Elliott urges to separate StubHub, Classifieds Group from core marketplace. : (Reuters) - Hedge funds Elliott Management and Starboard Value have taken stakes in eBay Inc (EBAY.O) and are pushing for changes including the sale of some of the e-commerce company’s businesses. In a letter to the company’s board, Elliott asked eBay to hive off its StubHub ticket sales business and eBay Classifieds Group as part of a plan the hedge fund says could double the company’s value.