I think Natalie Dormer would be the perfect choice.

nobody?

In looks alone, I would say that Dormer is an ideal choice. I have never seen any of her works before so I am not sure what type of actress she is.

I would probably choose Kate Beckinsale:

any body else?

@spiderbat87:  I'm not familiar with the actress you chose but she def. looks the part. Another choice might be Emily Blunt. Lady 'Nika though?...  first time I've heard anyone use her name like that and I can't say I'm digging it. 

No definitely not Megan Fox! Unless she can pull off an English accent well enough but I highly doubt it

No definitely not Megan Fox! Unless she can pull off an English accent well enough but I highly doubt it

Great thread, I'd endorse Emily Blunt, Leighton Meester, Olivia Wilde, Gemma Arterton, or possibly even Keira Knightley, but that might be pushing my budget. lol For me, the character's most distinguishing features are pretty transferable actress to actress, and most superficial ones, hair dye, wig, eye lenses, elegant, elaborate clothes, steam punk gear so on, it really leaves it open for quite a few actresses to play, to me, hard part comes with getting that tough as nails, motivated, snarky, sassy, grit across. Oh and plus the accent, but given steam punk's nature I would be okay if even that was a bit artificial sounding.