Nope. Haven't made it to Japan, yet. But, I know what you mean with the variety of techniques that fall under aikikai "curricula" that look completely different when demonstrated by different instructors. You can see that even in our high ranking "domestic" instructors.
I really don't like the term "style" either. But, organization may not exude the connotation we need.
How about a thread on defining aikikai?
That may be interesting.