I'm not finished yet, but I'm betting that the narrator in Bleeding Violet turns out to be unreliable. She's a hallucinating manic-depressive living in a town of demons, so I'm not entirely clear where the reality line is.

Also, not in speculative or historical fiction: Hope in Selling Hope lies day in and day out; in fact, the entire plot is premised on her lying. And most of Ally Carter's heroines (Gallagher Girls, Heist Society) lie constantly.