Currently, modules that use the PyGILState* APIs cannot be used with mod_wsgi, as mod_wsgi uses the subinterpreter support.
Graham Dumpleton and I spent some time discussing this at PyCon AU 2012, and we believe that the incompatibility can be resolved with a single API in the core: a function that mod_wsgi can call to set the interpreter used by the GIL state APIs to implicitly create new thread states.
This is still only a seed of an idea (and it's entirely possible we've missed something), but it's a place to start in resolving this longstanding incompatibility.