A screenshot of the quality from blu-ray and one from a DVD? I have a digital LCD screen so I'm guessing that the quality difference should be noticable.
It will be difficult to see the difference on any screen smaller than 32 inches or so. HD is meant for large screens and projectors to eliminate the NTSC artifacts that show up on large displays.
Is it possible to do a mock test using high res 16x9 tiffs cropped at the appropriate resolution converted into uncompressed avis and then encoded into HD and DVD mpeg-2 streams?? If not, would making an animation in both DVD and HD uncompressed res. and then encoding this to HD and DVD mpeg-2s?? The only thing is that making even a few seconds of high quality animation can take weeks if not months...