Well there is a huge source of models http://nwvault.ign.com/ containing a lot of work from lot of people (word-builders of old neverwinter nights 1 RPG game)
Actually theese models are not that easy to handle but I've made a support for loading them in Irrlicht.
Well MDL files are pretty complex containing not only mesh but as well lights and emitters and path walks (AABB) so I made only loader for models including animation and skinning.
Most models are binary files - this loader is designed for ascii version! (There exists convertor between BIN and ASCII version http://nwvault.ign.com/View.php?view=other.detail&id=1212)
NWN models may use special DDS textures theese aren't supported (its special DDS for nwn not documented.. ofc ) so there is again a tool to convert them to *.tga that should be lowercased and in same directory. (it may be DDS converter 2.1 but I'm not sure I got something from bioware page I can post it - if necessary)
It's first version and may contain some bugs.
(it is simple to use it - just set it between all other loaders and add lines CSceneManger than just load *.mdl)
http://www.mediafire.com/?2pe1ziw1gypa6io (some test models)
(Tested on 1.8SVN and 1.7.3 may work with other versions as well but not tested)
It may be added to future Irrlicht.