I believe they missed a pair of national championships, albeit in an individual sport...
Jeremy Khan, Duke '97, won an NCAA title in fencing, and Becca Ward just won one as well.
Maybe the tennis piece just meant team sports? If so, I think it could use the addition of that note, because right now it just says "Duke" and they are both representatives of Duke
That is a lot of national champions!
I'm not sure that the NCAA recognizes individual champions in track and field. There is a display of individual champions near Schwartz-Butters and (as of last semester) and they didn't display any track and field athletes.
That being said there are a number of boxing champions from years ago.
Let's not forget Rowbury.