Not guilty, though...
I can’t imagine who they would play. Stuart Townsend and Joseph Fiennes are both pretty young and good looking. Too young to be Scrimgour (sp?) or Slughorn.
Maybe Townsend is going get a dye job and be Bill Weasley?
Joseph Fiennes has a kind of dark, mysterious look to him, so maybe a death eater? I can’t think of any prominent DE in HBP aside from the usual suspects.