Recent interest cuts have spurred a refinance wave that is already paying dividends for subprime mortgage lenders. And many expect to ride that wave to the finish line in 2001. "When you get the type of frenzy that was created by the recent rate reductions, there are enormous opportunities," said Duane Kniffen, secondary marketing manager for QuickenLoans.com. "We’ve seen increased volume through all of our business lines."