Lucy Liu?(sp?) Michelle Yaiou? Even Angelina Jolie with a bit of cosmetic enhancement could do it! I forget the name of the woman who did the recent HBO/BBC characterisation of Queen Elizabeth would be formidable in that role...alas she's too old! Portman would be too wooden. Alice Krige could do the role in some of the books where Harrington has matured and climbed up in rank.
Some of the jacket art work on the books suggest a kind of Jolie look to the character...though the books suggest that Harrington herself doesn't think of herself as attractive.
The tree cat character...now thats a personality the animators could have a field day with!
They range from the 5'7" too short Jolie down to the you've got to be kidding 5'1" Liu. Now I'm prepared to accept a 5" downgrade to get Claudia Black, but 13"?