This Plater Script allows you to change the color and size of nameplates of particular units (for example Shadowfiend or other statically named units - including totems).
In order to for the script to work, the name of the unit needs to be added in the "Add Trigger" field (and press the "Add" button). After that, the "Option" table fields need to be filled in (creature type, color, width, height). If a table is not filled in, the default value will be used instead (e.g., if no color is picked for the particular unit - the default color in the left hand side of the options panel is chosen instead).
The script contains full protection against clever Hunter pet naming in arena. However, for protection outside of arena (world/duels/bgs) you may specify a creature type for the unit - this has the limitation that if the unit you're trying to remodel happens to also be Beast or Undead (retail only) just like actual Hunter pets the protection won't work.
Note: The height/width settings in the options are offsets from the default size. A value of -5 implies defaultWidth-5, not a width of -5.