According to reliable sources such as the NY Times and a quote from Steve Jobs himself in his biography by Walter Issacson, Apple is indeed working on a television product that may be released sooner than you think! The rumored set is said to replace the current Apple TV box by creating an actual set that runs the famous iOS and (to top it off) fully controlled with the Siri technology oppose to the traditional remote control...!
“‘I’d like to create an integrated television set that is completely easy to use,’ he told me. ‘It would be seamlessly synced with all of your devices and with iCloud.’ No longer would users have to fiddle with complex remotes for DVD players and cable channels. ‘It will have the simplest user interface you could imagine.” -Steve Jobs
Nick Bilton (NY Times) claims several people within Apple have confirmed the existence of prototypes and parts floating around, with a source even saying the television is “a guaranteed product” from Apple, with the only question being when the company will decide to unveil it and release it.