I suggest you check out the Abbey speaker designed by Dr. Earl Geddes. They are amongst the best speakers I've heard in my 30+ years in this hobby/obsession. When you take into account price/performance I put them at the top of the list. They punch all of the buttons you listed, except being full range. They are flat to 50hz and then roll off at 12db per octave. You'll need a sub or two to get the low end. IMHO, after having owned several pairs of full range speakers, the best way to get flat low frequency performance in most real rooms is multiple subs located asymmertically in the room.
While I've not heard the Merlins or the Salk's I can say they also have a strong following and appear to be a great value.
While I've not heard the Merlins or the Salk's I can say they also have a strong following and appear to be a great value.