Comcast-Spectacor wants to build a 10,000 to 12,000 seat arena to replace the Spectrum as a concert and minor-league pro sports venue, and it's been looking at sites in the Camden-Cherry Hill corridor.
  "It's so preliminary it's unbelievable," said Comcast-Spectacor CEO Peter Luukko when we asked him about site rumors. "We're closing the Spectrum in a year. We absolutely have to look around. We've had some confidential conversations in Camden County." The company has also looked into Atlantic City and Allentown.
  Would the company really leave its South Philly base? "If we could get some momentum for it, we'd love to stay here," Luukko said.
   Public arenas get built with taxpayer subsidies. Expect a lot of heavy negotiations among developers and politicians before the Spectrum's replacement is settled and announced.