The White House appears to be stepping up its languid pace in filling vacancies at key financial regulatory agencies. Two women have emerged as the leading contenders for a spot on the Securities & Exchange Commission. Martha L. Cochran, the top securities counsel for the Senate Banking Committee, has the backing of Senator Christopher J. Dodd (D-Conn.), a close friend of SEC Chairman Arthur Levitt Jr. But she has competition from University of Maryland law professor Ellyn L. Brown, a former Maryland securities commissioner. Meanwhile, sitting SEC Commissioner Mary L. Schapiro has been approached by the White House about a new post as chair of the Commodity Futures Trading Commission. The appointment of Schapiro, an SEC veteran and a former general counsel of the Futures Industry Assn., could lead to greater cooperation between the SEC, which regulates stock and bond markets, and the CFTC, which oversees options and futures trading.