I mainly seem to die on raids from being too busy to look down to my player window to watch my on HP. I am looking for a way to have them up front and center somewhere.
You could always set yourself as a target in your extended target window if you don't mind losing a slot on it.
I don't remember what is hard-coded in to which windows. I suppose theoretically you could replace the EQ button with a player HP bar, again assuming it isn't hard-coded, which for some reason I believe it is.