Is it possible to shoot such image with a AF-S DX Micro NIKKOR 85mm f/3.5G ED VR?

Is it possible to shoot a image like (http://www.facebook.com/photo.php?fbid=427278513985747&set=a.340971509283115.78878.203375569709377&type=3&theater0 ) with a true 1:1 macro lens. If not then what kind of lens is required to shoot like it… Consider other factors like ring flash… Tripod… Background… Etc. Are perfect.

Another question is is it a normal size image or enlarged? Is it possible to enlarge a normal photo (from a 16 mega pixel SLR) with such details?

Yes. You might well want some additional lighting, as if you want the greatest dof then you'll need to stop down a fair bit and a burst of flash will help prevent any movement blur (from the animal - i'm assuming the camera will be on a tripod).

This is one I shot with a 50mm f2.8 1:1 macro on a D300;

You'll be able to 'step back' a bit with the longer focal length.

As well as the megapixels, it's the quality of the lens that determines if you can successfully enlarge and crop an image. With a prime macro lens, the quality should be excellent, which means heavier cropping & enlargement are possible.

For that much magnification, the shooter may have added an extension tube to their macro lens

I would include some kind of macro flash set up, either a ring flash mounted on the lens or the Nikon R1 Wireless Close-Up system

Possible but unlikely. An extension ring and a good ringflash make it a lot easier. Biggest challenge is getting it to sit still though