Zilch
This...is...Caketown!
Personally ... I don't know one. Not even one.
That doesn't mean they are NOT out there --- i.e., guys who are physically qualified for Aviator but choose NFO instead .... it's just that in my experience --- there were NO B/N's at NUW -- or RIO's that I knew/met amongt hundreds --- who were not physically disqualled (usually visual acuity) from the left seat/front seat in the A-6 and F-4 -- none --- except the guys who used to be pilots and disqualled at the ship or something similar.
But: had I disqualled physically or operationally at any time during my Naval service ... I would have traded my Naval Aviator Wings for NFO Wings in a heartbeat.
Perhaps someone can answer this question for me: Why do so many NFO's wear glasses???
I'm not there yet, but I qualified as SNA and applied NFO instead. I'm not commissioned yet or anything, but I guess I'm that one weird guy in the bunch who would do that.