William- I hope I am none of the above, but I can tell you some of what I know: a letterbox DVD typically was not shot in exactly 16:9, so will not fill entire frame unless it is listed as anamorphic (I think). The 16:9 format is a compromise between typical cinematic and standard TV format. As far as the screen size, I will tell you that my 30" Loewe widescreen, when used in the 4:3 mode has a slightly smaller image size than my 26" Panasonic. My guess it would have to be considerably larger than a 36" 4:3.
Smart Analytical Geek Required
I am agonizing over a wide screen TV for my bedroom and I lack the brainpower for the following question: If I play the letterbox side of a DVD through a 32" widescreen TV, does it automatically fill the entire screen? If so, how big would a 4:3 standard TV have to be to project the same size image, excluding the black bars on the screen? Thank you very much.