Subprime lenders have gotten a temporary reprieve from new federal regulations that will likely make it riskier, and more expensive, to originate the priciest subprime mortgages. The Federal Reserve Board last week was scheduled to finalize long-awaited amendments to its rule implementing the Home Ownership and Equity Protection Act, a federal statute governing high-cost mortgages. But the discovery of anthrax spores on mail at the Fed’s processing center threw a wrench into those plans: the