THE casino kings in Las Vegas might want Britney Spears — but she's not interested. Sources say the pop tart, who is expecting her first child later this month, was pitched a long-term Celine Dion-type show a few months ago by Sin City deal-maker Jack Wishna. He pointed out that mother and child could avoid the grind of touring. "We'll bring the fans to you, instead of you going to them," she was told. But a rep for Spears said: "Not true, there is no Vegas show in the works."