While wearing the Tabard of the Scarlet Crusade as a Plate/Mail Player, you can buy Ensemble: Chain of the Scarlet Crusade or Ensemble: Scale of the Scarlet Crusade from the Scarlet Quartermaster at the Darkmoon Faire.
1. You will get Ensemble: Chain of the Scarlet Crusade.
2. You need to provide your account.
3. ETA: 5-15 Days.