Scrum-of -scrums is a good technique to scale the the Daily Scrum practice.  This works for some extent, but above a certain team size you do not get effective communication withing your project-team. Fortunately there is a solution to this: Story based stand-ups.

Some Agilists believe that practices like Scrum of scrums can only scale to a certain extent. Large teams need an alternative format for doing effective stand-ups which can be completed quickly. Story based stand-up sounds like an effective alternative for larger teams.

via InfoQ: Do Stand-ups Stand Up for Larger Teams?.

This is also confirmed by Kevin E. Schlabach:

Our pseudo-Kanban board (I say pseudo since it is not by the book) is already prioritized from top to bottom by the CEO/product owner. Now, instead of going around the room by person, we work from top to bottom. I play the role of scrum master, so I point at each card. The team speaks about what they did yesterday, what they will do today, and what is blocking them.