Maybe I'm the most unlucky person in this game, but I've been at level 81 for well over 2 months now, running Team Instance 4 times a day, and not once have I received the Shichiseiken from it. On average, I see it about once every 3-5 days, and even had an instance about 10 minutes ago that had THREE of them in the prize screen for a single run, but have never hit it.
Before that, the book was a little elusive, but that really only took about 3 weeks of runs before I got it.

Is there anyone else who's getting horrible luck with any of the 81+ ninja tools? If so, which ones?