Earlier this year I checked out Remington's NV monoscope. It's a 3rd gen. device and you buy an adapter to slip that puppy onto the objective eyepiece of your riflescope. Instant night engagement capabilities. Drool.
Drawback in the model I saw was lack of rubber coating for shock and waterproofing. Suggested changes to the factory rep. Other BIG drawback is the $5k price. Ouch!