I was told by CSR to post my suggestion for an add-on here. I read the rules and I understand the position of an enemy cannot be tracked. However, I wonder if it's possible to create a targeting system to allow me to put a marker on a mob that only I can see (being dps I wouldn't have lead). It would help a great deal tracking the position of my target w/o causing any confusion among the team. The tank can target mobs he wants attacked using the game marking system, but the healers can tag the tank and I can keep up with any of them should the need arise.
It is possible to decorate nameplates (example: Target Nameplate Indicator or Healers Have to Die ) so this is not entirely unfeasible, but I'm not aware of any addon that lets you do what you describe exactly, that is put a persistent mark on a specific mob's nameplate.
If you only want to better track your current target and not mark an arbitrary one then the first addon I linked or something like rTargetPointer could probably help.
Thank you for taking the time to respond. I am trying the target nameplate indicator. It seems to be just the thing I'm looking for! I'm not a fan of the symbol of the indicator, and there seems to be this really complicated way of changing it to other things like skull and crossbones etc. But it will do for now, and again, thank you for your response. :)