They are the exception. Over the last forty years many have been tried and almost all never made it. Again I point to Bobby Douglas who was 6'4" I think.
Ben Roethlisberger 6'5"
Although we really don't know how he will shake out, he has won a Super Bowl(***cough cough**)
Brad Johnson 6'5"
Has been in the league 15 years and Won a Super bowl..