Pyrit patched for MPI-support and running on a cluster with 16 GeForce 8800 GT has reached 89.300 PMKs/s according to this post. This is equivalent to around 1.460.000.000 rounds of SHA-1 or 749 Gbit of data processed every second.
Update: The author of the posting mentioned above sent a link to a video showing Pyrit on 14+1 nodes…
Pyrit 