I spent almost 15 years living and working in Seattle, so let me address this rumor.
It's hogwash. The reason the Sonics moved to OKC is because Stern was trying to extort the city of Seattle into buying the NBA a brand new arena. This, on top of the city and the state basically buying both Safeco Field and the Seahawks Stadium. Seattle said nope, no thanks, nothing wrong with the Key Arena. We've already been shafted for two expensive stadiums for perpetually bad sports teams, so we're not funding a third. So Stern happily blessed the franchise sale to the guys in OKC. Unless someone in Seattle is magically changing his or her mind, and buying Stern a new half-billion dollar arena, the NBA is not putting another team in the Pacific Northwest any time soon.