Yes, two Quadro Plex Visual Computing Systems (VCS) can be used in a single certified SLI host system to enable the following:
8x GPUs (Model II)
16x Frame Synched Dual Link DVI (Model II)
8 x HD SDI Outputs (Model III)
Additionally, a graphics supercomputer cluster can be configured by rackmounting multiple VCS nodes together via NVIDIA G-Sync.