The concept I have so far is an ambitious noblewoman who is skilled at manipulation.  I am thinking a daughter of House Dorcha who spent some time away from Haven to learn the Bene Gesserit ways.  She came back more or less the same, but now has a secret ambition to win a place for the house in the Lansraad and make their assassins players on the galactic stage.  I have made a noble Envoy, who would be a good fit for the Ruler, Consort, Heir, or Envoy house roles.