I am slowly, manually, constructing an interface to an external-API library (built in .cpp) using LibraryLink. The semi-frustrating thing is that I have a swig compatible .i file for the API that the authors have made available for generating python, c# wrappers of the dynamic library.
I looked a little at @Szabolcs LTempate which is a very nice start at such a thing, but it would seem like someone out there somewhere might have written or played with a Mathematica back-end for swig at some point - yet I am unable to find anything.
So this is basically a solicitation / placeholder / common point in case someone has / does / wants to do such a thing.