In an interview published late last week, Sirius Satellite Radio CEO Mel Karmazin raised the prospect of a merger between his company and rival XM Radio. When asked about the possibility that the two might join forces, Karmazin demurred at first, saying that he couldn’t really discuss it. Then he did: "I have focused my entire career on shareholder value and wealth creation. Often mergers allow for that. I combined my radio company with CBS, and I combined CBS with Viacom."