Also, the image posted of R2 shows a big difference too... I'm not sure what the second "downconverted" image is supposed to be, but the third image (which I assume started life at 1080) shows the same increase in detail.
Since this would be a fairly painless and straightforward process for someone who has the HD files and is good with DVD encoding, it sure would be great to see someone make a dual-layer DVD downconversion from the HD masters...
Or at least do a few scenes in a side-by-side test to see if, when watched on a TV, if you can see a reasonable difference...