I was wondering the same thing.
For sharpest DVD quality, I have:
Star Wars: DeEdV2 (amazing authentic coloring on this one)
Empire: ESB 2.0
Return of the Jedi: currently no authentic alternative
Then for what the films would have actually looked like, we have:
Negative1 scans (not yet released)
And for 1997 editions I see no high-quality NTSC alternative.