Yes actually, back when I scripted/hosted "Land of the dead". I incorporated the gun models from Resident Evil 3. I also added Nemesis as a boss ftom RE3 too.
The issue of using outside game models arises in the version of directx used to make it. Models from later Directx versions can still be used, but they may not render properly due to featires in newer directx not being usable in older versions. In addition while nwn has no hard limit to the amount of polygons a model can have, more then 10,000 polygons causes lag spikes(ala horse lag).