Can you legally use a spotlight? You'll get better resolution than with an image intensifier or a large objective low power scope. I'd suggest an led or HID focused illuminator depending on the range you need.
When there is not enough light to see in color the human eye's resolution drops by about a factor of ten. A full moon overhead is at the edge of providing any color vision. No optical scope can make the image brighter like an image intensifier does. It takes a 10x70 scope to restore "naked eye" resolution under moonlight less than a full moon. That's with the eye dark adapted.