NEW YORK (Reuters) – One of the hottest new trends in fashion is emerging from an unlikely venue: law school. Fashion law is a burgeoning niche practice in New York and Los Angeles, both hubs of the approximately $200 billion U.S. apparel market, with both legal firms and design houses hiring specialist attorneys. Their charge is to negotiate real estate deals, advise on mergers and acquisitions, deal with employment disputes and, in some of the most high-profile work, litigate copyright claims. Those claims can be crucial to fashion labels. …