Digging around the iOS 7.1 software developer kit has revealed that we may be seeing Siri integration with Apple TV. The code refers to Assistant, which is Apple's internal name for Siri, in relation to device family 3, which is Apple TV.
It's unclear exactly how the feature might be implemented, but even if it's something as displaying results on the big screen when an AirPlay connection is active, that would be good enough for most folks. If you wanted to get creative, this could indicate a new Apple TV with a mic built into the remote, but that's entirely in the realm of speculation.
How would you guys like to see Siri used on TV? Would Apple be able to do it with existing iOS devices, or would it need new Apple TV hardware?