Home equity lending is booming in 2004, as more favorable market conditions neatly complement long-term business strategies at most major lenders. Production of closed-end second mortgages and home-equity lines of credit has boomed to $230 billion in the first nine months of 2004, according to industry surveys conducted by Inside Mortgage Finance, an affiliated newsletter. That was already well beyond the estimated $178 billion of home-equity loans originated during all of 2003. …