How super of super nations? I've had 3-4 in every game that I would consider super nations. China always seems to have at least one, but unfortunately it's big enough that it sometimes has two. I also had a Viborg that was basically Muscovy/Novgorod/part of Sweden that made me sad I was playing on the north of the Black Sea. Same game saw a Romagna(sp?) that had half of Italy, and somehow ended up with most of Hungary and part of the Balkans not long later. They turned out to be a lucky, but I don't know how much of that they started with vs possibly took shortly after start (would have had to have been in the first 10-20 years).
Not sure if those qualify like what you're seeing, but they've been pretty strong, especially those china nations. *shiver*