Karlaan 
In The Shadow Rising ("A Truth to a Viewing") Siuan is complaining that Danelle has let an extra 300 laborers in to build the new wing of the library. Danelle is described as dreamy even for a brown, WoT describes Mesaana along the same lines.
When Siuan is arrested these laborers attack the White Tower and are backed by Hammar and the Blue Warders and the split starts. This is obviously a set up, which begs the question why would Danelle allow these laborers in when she is on Elaida's side. Two reasons - she is a complete airhead and didn't notice the extra laborers or she is Black. Note Alviarin is the first to know of Elaida's intentions, so there is plenty of time to prepare. However Alviarin is a head honcho of the Black Ajah and knows all the Black sisters as she proves when she sent fifty non-Black sisters to the Black Tower, but she does not believe Danelle to be Black. Which leads me to believe that she is Mesaana...
Note in this passage Laras' suspicious behavior, she looks for Min when the fighting starts and threatens to lock her in her room, then Min tells of her intentions of helping Siuan escape and is surprised when Laras agrees to help. She is not sure how Laras got her to reveal this - Compulsion? Min has trouble opening the lock and the way Jordan has written this part it appears that Laras may have used the One Power. Could Laras be Semirhage with Siuan/Elaida her "willful female charge."
Other options for Semirhage would be "Alwhin with Suroth," "Aes Sedai with Tenobia," or "A Daughter with the Empress."
wotmania says: To be honest, it has been too long since I read this particular passage, and I really can not say what I think about Laras. As for Mesaana, I think Danelle is certainly one of the prime suspects. I have a sneaky hunch we might find out who Mesaana is in the next book (or at least get a lot more clues) as they start figuring out who the Black sisters are in the White Tower...
Karlaan
Nice!