Anything in letterbox IS 16 x 9, and the channel is 1080i, so it is HD. The difference is, for some reason, they're not pre-stretching the picture.
Not true. Wide screen and HD are two separate issues. I have seen widescreen movies on tv's since the 1960's. they had bars top and bottom, but it certainly wasn't HD. Stargate atlantis has always been presented in widescreen, but it wasn't HD. Just because your TV or DVD player scales it up to 1080I, doesn't mean it's HD. That's why there are DVD players that scale up the picture to "Near" HD quality, and then you have other players that are HD.
Stretching the picture does not give you HD either. That's why most people think TBSHD stinks. Streching the picture distorts what you see.