The Apple rumor mill has been in high gear these days. What with reports of an iPad Mini, the new iPhone, and the iTV, speculation about what Apple’s got coming down the product pipeline has been rampant. Reports about Apple’s supposed foray into the HDTV market with a device alternately called either the iTV or the Apple TV (not to be confused with the set-top box), have played a pretty sizable role in that speculation. There has been speculation about the TV’s size, its shape, its price, and its features (Siri? FaceTime?).

One feature that’s bounced around the rumor mill but hasn’t picked up a lot of traction, though, is motion control. This rumor – often dismissed – suggests that Apple’s HDTV will be getting the same kind of motion- and voice-activated interface that Microsoft introduced with their Kinect system. With a system like this in place, you wouldn’t need Apple’s remote app on your iPhone or iPad. You wouldn’t even need a physical remote. You could control your TV by talking to it and waving at it. This, of course, could pose a problem for enthusiastic sports fans, who may get tired of hearing Siri say things like “I’m sorry, I don’t understand ‘Pass the damn ball.'”

At any rate, while a motion controlled iTV/Apple TV is still very much in doubt (as is the TV itself, for that matter), it appears that Apple really could implement the technology if they want. In fact, according to a report today from Business Insider, Apple’s “answer” to Kinect is older than Kinect itself. According to “a source familiar with the software,” the software started out as a hack designed to have devices shut themselves down when they detect the user leaving the room or waving goodbye. It was originally developed in 2005.

When Apple decided to hang onto the software, the source assumed it was going to be incorporated into Macs with iSight cameras built in. That, of course, never happened, and Apple has apparently kept the tech under wraps ever since.

The revelation that Apple has motion sensing technology already in the works prompts BI to suggest that it could go into the rumored iTV. Combined with Siri, this technology would instantly give Apple a strong competitor to Microsoft’s Kinect system, which has rapidly evolved into far more than a mere game controller.

Of course, the technology could also be used in other ways: it could still be implemented in Macs, or it could be adapted for use in iOS devices, perhaps as an answer to Android 4.0 Ice Cream Sandwich’s Face Unlock feature. Or it really could go into the iTV. Always assuming, of course, that Apple really is making an iTV, and really does plan to bring it to market. While that seems more and more likely of late, the fact is that the device is still basically just another rumor.

But if it isn’t just a rumor, if Apple really is working on their own HDTV, then motion sensing technology (along with Siri, FaceTime, the App Store, and a few other unique Apple touches) could make for a pretty revolutionary HDTV, even if Apple doesn’t get the content delivery deals they reportedly want for it.