mod_python should be a fairly easy server to implement. WSGI would probably be a handler, similar to the publisher handler. Code written for mod_python is another matter. I don't think there's any way to support that, because you'd essentially have to recreate an apache-like environment without using Apache. Hopefully anyone who has programmed directly to the mod_python API realizes they have eschewed any portability; though many frameworks built on top of mod_python could be ported to WSGI, since most of those don't really use many mod_python-specific features.