Possibly also Oscar from Rose of Versaille, but that would be sort of missing the point.
A couple of people seem to be suggesting PhoenixFeathers/Peri belongs here but I can't see that myself. --Kazuhiko
One character that comes to mind would have to be Mari form the Project A-KO series. --Tsunami
And while I am thinking about Project A-Ko, Spy D is also female, but you couldn't tell initially --Tsunami
[Secret Garden] (and I'll let you guess which of the two I'm talking about). See [here] for an explanation (of sorts). Unfortunatly the translation hasn't even got far enough to introduce the character in question yet... --Kazuhiko
I would hope you're talking about the one on the left - but I'd be much more inclined to agree with ThatCannotBeHuman? for the one on the right, who looks rather Neanderthal. [Reads link] Ah. I see.