The Combat Focus feats can let you change your target as an immediate action, and there are alternative Dodge feats (such as the movement based one from RotW, or Psionic Dodge), but they don't select a target and thus wouldn't work with Defensive Throw as they don't designate a person to recieve your dodge bonus.
One thing I've always toyed with is Combat Focus + Defensive Throw + Elusive Target...seems like a fun build.