I have released pwig, an SWIG extension that allows new language modules to be developed using Python instead of C++.
To stop any confusion I'll explain it another way: It's a Python SWIG wrapping for SWIG itself!
It also includes a module (obviously written on Python :-) to generate wrappers for SWI-Prolog.
pwig home site is at http://pwig.sourceforge.net
Comments, questions, bugs, patches, new language modules, etc. are welcome!