Imaging-resource has posted first high ISO comparison on new released Nikon D5 with Nikon D4S and Canon EOS-1D X full frame DSLR cameras. The Nikon D5 is already shipping, you can now pre-order Nikon D5 through Amazon/B&H Photo/Adorama .
Nikon D5 Vs. Nikon D4S at ISO 102,400:
Nikon D5 Vs. Canon EOS-1D X at ISO 102,400:
You can read full comparison of Nikon D5 Vs. D4S Vs. 1D X high iso comparison at Imaging-resource.