Well, at the risk of spoiling Aaron's unveiling, I'll have to tell you guys what these are. 🙂 (Sorry, Aaron, but by doing this little teaser, you started this little guessing/speculation game.)
The definition of a vertex is:
1) (noun) the highest point; the top or apex
2) (anatomy) the crown of the head
3) (geometry) a meeting point of two lines that form an angle or the point at which an axis meets a curve or surface.
Maybe #1 provides the rationale for the name, and these are being marketed as the "pinnacle of all irons." I doubt #2, has anything to do with it (though that might be different if this was a driver/FW). But it's #3 that I think is particularly interesting, and it is this definition on which I basing my guess.
My guess is that these irons represent the point where two different, but related technologies meet: SL and variable length irons. This would suggest a set of irons where the longer irons (4 and 5 or 5 and 6) can be built to a longer length than the shorter clubs. The hollow, lighter heads on these irons will enable us to build these clubs longer, but still hit the same MOI/SW as the shorter irons.
And there you have it.