Yamaha N12 12-Channel Digital Mixer with Firewire Interface
The N12 originally did not support cascading the boards to expand the number of channels but the system does support the Yamaha mLan standard which supports up to 16 channels on a single firewire. It's very difficult to get a final word on whether these can be cascaded or not.

Background image by Pauline Moss. at http://paulinemoss.deviantart.com/art/Stars-307119758