I tested out a few shots at maximum ISO ad then forgot all about them. Well, today I took them out and of course expected the pictures to be unusable. The focus point was the glass at the back, and it came close to nailing the focus on the head.
ISO 25,600, straight from the camera:

(click on the pic for a bigger size to see the real ugly... lol)
It is really harsh and visible, and not something that I would share with a paying client, however, it doesn't seem as intrusive as my D200's ISO 3200 was... with a lot less noise at the luminescence level.
The same picture again, but this time I just applied a hefty amount of noise reduction using Imagenomic's Noiseware Pro:

(click on the pic for a bigger size)
Now, it is still not what I would call "client worthy" as you see a ton of artifacts all over the place... but, one has to remember... ISO 25,600... that is as high as I can get the camera to go and as bad as I can get the noise to get and still pull back into some semblance of a usable picture, which I think it is... very usable. I don't see the great loss in detail vs applying the same amount of NR to a D200/ISO3200 pic.
Now, before people say all this is, is a bright room pic at ISO 25,600, which would NOT show near the same amount of noise... I ask that you look at the
EXIF:
Exposure: 0.04 sec (1/25th)
Aperture: f/8
Focal Length: 70 mm
ISO Speed: 25600
Lens: Nikkor 70-200 @ 70mm
That's 1/25th... HAND HELD at F/8 and ISO 25,600. The room was dark... very dark (as in past 8:30PM dark). Now, there was one light turned on, but it was from the other room (in the kitchen, this pic was from the dining room), and it was a single 40 watt light that is above our stove in one of those fan/light units (that thing that draws out all the smoke when you burn something on the stove... lol).
Again, I am pretty stunned with what this camera can do... and even when it does "bad", it's not that bad and can be pulled back to what I call a savable state.
This has to be a wedding photographer's dream camera!