7. Alexa Davalos
Another actress with a Joss Whedon link, Davalos played the recurring character of Gwen Raiden in the fourth season of Angel. However, I personally think that it was her role as Jack in The Chronicles of Riddick an otherwise pretty awful film, apart from her and a scene where Riddick is armed with a tea cup which shows that she could play a good Jessica Jones. For whatever reason she doesn't have a massive filmography, but she's still acting she has a film in post-production at the moment and is in the cast of Mob City, due to debut in December on TNT. She is about the right age range for the part, and I think could take on both the grungy role of Jones herself as well as the more upbeat Jewel flashbacks. She has also shown in Chronicles of Riddick that she can perform in a quite active role which may be required at times in the new series. She would be a little more unknown than the actresses previously mentioned on the list, but only to the extent where fan boys who didn't recognise her immediately would Google her name and then slap themselves on the forehead when they remember where they'd seen her before.