SAN FRANCISCO (MarketWatch) -- The collapse of Lehman Brothers and the sale of Merrill Lynch have left questions about the future of the last two major, independent Wall Street brokerage firms, Goldman Sachs and Morgan Stanley, experts said Monday. http://www.marketwatch.com/news/sto...x?guid={BB47D94C-93CE-43D8-8A74-0D12F9EBA693}