A lot of the expansion warbands - the GW ones - say something about hired swords in the warband description.
Amazons: Not one of us: Due to the Amazonsí isolationism and suspicions about other races they never side with anyone else. For this reason, the Amazons may not have any Hired Swords or Dramatis Personae unless they are actually Amazons themselves.
Kislev: May Hire: A Kislevite warband is allowed the same selection of Hired Swords as the Human Mercenary warbands from the Mordheim rulebook.
Unfortunately, not all say.