David Lee, who helped financier Gary Winnick build Beverly Hills-based Global Crossing Ltd. into one of the world's largest cable telecommunications companies, has quit Winnick's shop to become a venture capitalist. Lee joined forces this week with Rudy Reinfrank and other partners at venture shop Rader Reinfrank, also in Beverly Hills. Lee and Reinfrank have formed a new shop named Clarity Partners, and they have already engaged premier brokerage Merrill Lynch to raise $1 billion for a new venture fund. Also leaving Global Crossing to join Clarity Partners will be Barry Porter, another senior executive. The firm will focus on financing Internet-telecom infrastructure start-ups, Reinfrank said.