Well, it looks like the search for the actress that plays Bree is over and her name is Jessica Rose. Through some serious Google cache searching it has been discovered that Bree is in fact played by Jessica Rose. You can see some of her pictures in the Google Cache of her pictures page.
I’m sure a lot more of this is going to break through the day, but the search is almost over.
You can also check out the forum where many of the people investigating her gang out.