Jeff, after reading the additions to your Japanese DVD review:
If the Japanese DVD is 1.51 on your TV and 1.81 in the computer capture, removing the overscan, wouldn't it be safe to say that the Cirterion LD may be wider if there were a way to do a computer capture of that image? It might be 1.66 after all, and your TV may have terrible overscan.
Another thing I noticed in your comparison is that it seems that Orson is thinner in your LD image than in the DVD image. This could account for some of the missing width. Just some thoughts.
I mentioned to you privately, but I thought I'd bring it up here, too, that a good side-by-side comparison would be the multi-colored film cans, three of which have Oja Kodar's name on them. You can't read the top and bottom cans on the Japanese DVD, but I'm sure the F for Fake I taped from TMC last year showed all three clearly. Trying to remember, as that tape now holds 6 straight hours of Teletubbies for my 2 yr old.