My character concept is a Dhampir noblewoman Rogue/White-Haired Witch/Noble Scion.
She is a (somewhat reluctant) blood-drinking fanged Dhampir whose favourite tactic is to appear harmless (Bluff, Sneak, etc) then Sneak Attack with free Grapple and subsequently Pin with her hair, followed by a Sneak Attack fang bite on the pinned victim.
Assuming all rolls succeed, the first (hopefully surprise) attack will be hair damage + Sneak Attack + free Grapple. The second round should then be converting the Grapple into a Pin. At that point it becomes very one-sided and all subsequent rounds can consist of fang-based Sneak-Attacks as the opponent is denied Dex to AC and cannot move or attack until he escapes. Blood everywhere. Burp. Much hand-wringing and moralising.
As the concept relies on both multi-classing and a strong Sneak Attack, however, I wondered if anyone had come across a Feat to allow the Witch (and Noble Scion) levels to count as Rogue levels for the purpose of Sneak Attack. It is a bit of a long shot, but similar level substitution Feats are available for the primary powers of other classes. I have searched through the Feats but these things have a habit of hiding in unusual places, having titles that don't make them easy to spot.