bozzykid basically covered the technical answer to the question (and I included a link to a thin device to attached to an LCD HDTV from Panasonic that would have to endure the very same perceived challenges of distance, etc.) I don't think there is a tech-based limitation to being able to do this. There are certainly location-based issues (for those who choose to store it away from roughly center of the screen, above or below it). But this was about a next-gen
TV and something someone shared as of interest to them (I'm not much interested in this feature myself).
I can say that I had a dial-up based box about the size of the
TV in 1998 or so which could connect with the same box at the other end of the connection. Quality was not great, but it was (pseudo) video conferencing on the cheap using 2 TVs (no computers) and a small set-top box. If you want to communicate that way using TVs, you find a spot for the cameras that works well for you.
These days, most HDTVs require a stand if you aren't hanging them on a wall. Stands usually have shelves or at least the platform on which the TV itself sits. If so, this
TV with a facetime camera could go there (and work well). If the TV is hanging on the wall, someone wanting to do this would need to think about a shelf above or below the TV. OR, they could pay the $160 for the Panasonic solution (or similar for LG, Samsung,etc) to be able to Skype video conference using non-Apple tech.
The point being: if iDevices are going to have the hardware built in anyway, it might be one more "wow" thing to tout in a next generation. Is it something to win over everyone? No. But Facetime is not something that wins over everyone who buys the other devices either. It's just "one more thing" that might win over a few more people, where a few more people on iDevice scales can add up to a lot.
I do recall the happiness that old 1998 device brought to my parents when we were able to video chat through the TV with a small device way back then. Now with broadband on both ends and a panasonic/LG/samsung/etc dedicated device or maybe a gen-3
TV, lots of other people could get that same joy. If the latter, lots of those other people can get the other joys of an
TV, rather than just a more expensive, dedicated device that does nothing but Skype videocalling.
Again, I'm not personally in love with this particular thing. I just don't think the guy who showed some interest in it is wrong because others think it makes no sense. Last year, I found great fault with the iPad for not also coming with an isight camera. You would think I told someone their kid was ugly or something. It seemed like hundreds of cheerleaders bashed and bashed about how stupid it would be to put a camera in an iPad, etc. A short while later, Apple shows the way forward with Facetime and now I see some of those very same people gushing about how great it will be to have a facetime camera in the new iPad, how they're buying one on day 1, etc. Apparently, people are only wrong about things until Apple shows that they are right... at which point the cheerleaders are quick to flip flop.
Or, on a more personal level, iDevices can do all kinds of stuff I personally never use. But just because some of those applications don't make sense to me doesn't make it wrong for all. If the guy would like THIS iDevice to have a FaceTime camera for his TV, it certainly can't be as bad as me- last year- arguing why the iPad should have an iSight camera for THAT iDevice.
