A few more interesting things:
DVDBeaver has a review/comparison of 2001: A Space Odyssey with lots of picture comparisons. Among the releases are the MGM 1998 DVD (supposed to be mostly identical to the Warner 1999 DVD) and the Warner 2001 "remastered" DVD.
http://www.dvdbeaver.com/film/DVDReview/2001.htm
The Digital Bits also has a comparative review of the three DVDs in question -- 1998, 1999, 2001 -- but it is not comprehensive.
http://www.thedigitalbits.com/site_archive/reviews/2001.html
The real question is ... which of these DVDs, if any, correspond to the Criterion CAV 3-disc Laserdisc set (1989) or the MGM CAV 3-disc 25th Anniversary Laserdisc set (1993), as regards coloring and detail, respectively.
And did you know that the recent PBS-aired TV special The Beatles' Magical Mystery Tour, of untold ages ago, included out-takes from 2001 as background to one of their songs?
So alleges h2g2 - '2001: A Space Odyssey' - the Film
http://www.h2g2.com/approved_entry/A533413
under it's Did You Know...? section.
"Alleges" because if one thinks of the obstacles of Stanley Kubrick and copyright laws, it doesn't seem likely, even for The Beatles. (More likely is similar footage re-colored in kind.)