The AstroScope 9350 night-vision image intensifier mounts between camera and lens to make dark scenes (below 10-4 lux) easily photographable. The EOS-P and NIKS-P models are for Canon EOS and Nikon AF cameras, and are powered by the camera's battery.
Electrophysics says its AstroScope module won't stop you using all your camera's normal functions, and that it can produce images with little to none of the vignetting commonly associated with night vision shots.
Pricing isn't on Electrophysics' site, but a quick search turns up a price range of about $US5000-$US6000. A module for Canon's XL series video camera is also available. [Electrophysics via RedFerret]