Really interesting ideas, everybody!!!! Claire Danes would have made a good Marie, and she was so excellent as Beth in "Little Women" (1994). Kirsten Dunst does bear a bit of a resemblence to Fiona Fullerton who portrayed Anastasia in "Nicholas And Alexandra", and she was the voice of young Anastasia in the animated movie. I remember Angela Cartwright in "The Sound Of Music" - I grew up with that movie and I have it in my personal collection!!! Julia Stiles would have pulled off the role of Olga very well, although again, blue contacts needed!!! Milla Jovich is an interesting choice, too, since she was born in Ukraine. Another young actress who would portray one of OTMA well is a British actress named Amelia Warner. She was briefly married to Colin Farrell and appeared in the movie "Quills" (2000) and in the title role of A&E's film production of "Lorna Doone" - see it, by the way, it's gorgeous!!!! - here is a link to a site with a photo gallery of her: http://www.ameliawarner.com/Gallery.htm
And check out this Lorna Doone site
http://myladylorna.tripod.com/characters.htmJust to give you and idea of how well she wears period costume, and again, she would need blue or grey contacts.
In closing there is one more actress who comes to mind:
Kate Mamberly, who played Mary Lennox in "The Secret Garden" (1993). She has most recently appeared in "Finding Neverland" (2003) with Johnny Depp, Kate Winslet and Julie Christie. I don't know if there are any sites featuring her or dedicated to her, but if you find any, let me know. I thinks she resembles Marie a little, but again, she'll need blue contacts to have "Marie's saucers"!!! Let me know what you all think!!!!