I have this nagging feeling that she may be another fanmade Vocaloid character like Yowane Haku, but I've gone through a couple of Vocaloid fansites with no luck in finding out who she could be! I wish we could at least see what the number on her right arm is, then I’d have a better clue!
For now, I’ll be featuring her in the Unknown Section until I get a better idea. Thanks to Ian for sending this!
EDIT: Thanks to Heimi for letting me know she is Kasane Teto from UTAUloid!