Many mortgage bankers are acknowledging that profit margins are being squeezed by increased competition, but they say the pressure hasn’t yet caused major faults in the market. “We’re seeing competitive pressure across the board,” said John Gellhausen, executive vice president in charge of mortgage banking operations at National City, during a discussion at last week’s National Financial Services Conference sponsored by Fox-Pitt Kelton. But what’s happened so far is pretty much in line with expectations for…