Sometime early next year, Apple will start selling a new item, aside from (possibly) the iPhone or touchscreen video iPod. Oddly, this was announced a few months ago–something that is almost never done by Apple, previewing an upcoming product. But as with Leopard, not everything was revealed about the product. Here’s what we’ve been told:

The set-top box will sell for about $300. It will have ports in the back for component (RCA) video and audio, USB2, Ethernet, and optical audio. It will come equipped with WiFi. It will be able to automatically locate any computer in your house on the network (wireless or Ethernet), and stream photos, audio, and video between the computer(s) and the set-top box. There is a control interface similar to Front Row. “iTV” is not its real name, just a placeholder.

The idea as stated so far is that the unit will be like a media center and allow you to control all the media on your Mac (or, presumably, any other iTunes-connected computer) and see it or hear it on your TV and stereo system.

Now, just that alone doesn’t really sound too spectacular; the same could be accomplished by using Front Row and hooking up your Mac to your TV/stereo with cables. Even if your Mac is too far from your TV to do that, would you still want to pay 300 bucks just to stream like that?

But there is more. For example, the WiFi is not specifically identified, but all new Macs for several months now have come equipped with a new WiFi protocol called IEEE 802.11n; existing protocols can send data at a max of 54 Mbps (6.75 MB/sec), while 802.11n can send at between 2 and 5 times faster than that (potentially as much as 10 times faster, eventually). But the WiFi-n is not activated–it was kind of slipped in there quietly by Apple, and will likely be turned on at some near-future date. It is a no-brainer that this is being done, at least in part, to prep for the iTV.

But the big speculation is over what Apple isn’t telling us. Obviously they’re leaving something out. The iTV as described is very unimpressive, and it would be hard to believe that Apple could sell too many.

However, two missing details could give a hint as to what Apple might be planning. First is the question of a hard drive, which would allow the box to do more than just streaming. And the other would be how strong the DRM is on the box, making it a possible home for more than just ordinary video. These are big items if you want to see the unit as something worth all the secrecy and development.

In discussions with my family, one possibility came out as a good possibility: a new rental video system. The old Blockbuster-style brick-and-mortar system is beginning to die. Some people would rather pay a bit more at Wal-Mart and own the movie. Others use the alternative Netflix. But both rental paradigms have drawbacks. Brick-and-mortar rental shops often have OK availability, but you have to travel back and forth to the shop, and everyone hates the time restrictions and late fees. Netflix does away with both of those problems, but availability can be a huge problem with them, and turnaround time using the postal service can take days.

Imagine Apple coming up with a third option: order a movie over the iTunes Store. It then streams to your iTV, where it sits within the nicely DRM-protected hard drive. You may then play it on your TV as much as you want for the next 3 days, after which time it disappears. Availability could be 100%–a movie would never be out of stock, as they would be digital–and delivery would be nearly instantaneous. Even better, if Apple could swing a deal with the movie studios like Microsoft did with the music labels, a monthly subscription fee could substitute for the per-title system; this would be essentially the same service as Netflix, but without any of the disadvantages–save for the initial expenditure for the set-top box.

Standing in the way of this might be the greed of the movie studios: with DVD sales driving profits for them more than even box office sales, they might not want to risk cutting into that market for a much lower-priced alternative. Also, there would be other disadvantages: the quality of the video would likely be the same as the current iTunes Store videos (barely NTSC, not HDTV for certain), and special features on DVDs would not be available. Also, movie studios would likely be hesitant to join, meaning a small library to start out with (like Apple’s current buy-to-own movie download service, which currently features only several dozen Disney titles).

However, if this is what Apple is planning, and it they can make it work, it could be to movies what the iPod is to music–which I would imagine is what Apple probably set out to do with the set-top box in the first place.