If they did release a set top box, it likely would be compatible with cable companies only. That is, unless they worked out a deal with DirecTV. Like TiVo, DirecTV requires a different breed of set top box. That being said, I've always thought of DirecTV has a forward thinking company. They are always looking for ways to differentiate themselves from the cable companies, so a deal with Apple would do just that. That being said, it wouldn't be feasible. DirecTV is great at delivering content, but not Internet. Any Apple TV set-top box would require connectivity. When I had DirecTV, I needed to have a separate deal with a cable co for Internet. I cannot see Apple delivering such a fragmented experience.