In two days, I wrote a simple interpreter for NCS files which can be embedded in C++ applications. It processes scripts compiled with nwnnsscomp and a custom nwscript.nss (provided by the author of the application, contains the API available from the script).
If anyone is interested, I will upload the sources for testing. If there already is a complete implementation, I won't bother.

Though I don't have a specific need for this within Kotor Tool, I am always interested in seeing what other people enjoy working on. Your interpreter sounds like and interesting and ambitious effort, so I, for one, would love to see what you've produced.