There was a Focotar 3 in prototype form only. Never built in series.
I have a problem with the Focotat 2 in that it does not have a flat field, not as bad as the original, but still not flat. It is very sharp and I can`t see why you need anything better.
My personel favorite is the large front element version of the first. It is about double the normal size. They were designe/built by Schneider when Leica finally realized the original was trash for much bigger than 5x7, and they were not ready to produce the Focotar 2.
I currently have the second version Focotar... Before the Focotar-2, and after the Focotar with writing on the face. There was a Ic on Ebay recently listed with a Focotar-4, and I have seen references in the past. I wonder if a small number of Focotar-3 could have been distributed, and being the fourth actual incarnation, could be refered to as Focotar-4's?