By Tommy Reggiori Wilkes LONDON (Reuters) -Britain's Revolut said on Tuesday it was exploring buying a U.S. bank to accelerate global expansion and preparing to launch consumer credit in its home market, as the digital finance firm seeks to encroach further onto the turf of traditional lenders. The London-based company has emerged as the most valuable of a crop of European financial technology firms and is seeking a $75 billion valuation in a secondary share sale. It has 65 million customers, topping ...