I run several Python webapps, and I wouldn't bother with mod_python or mod_wsgi. They're bad ideas (I can go into more detail on why if anyone cares).
Instead, I proxy from my front-end server to a standalone Mongrel-like webserver that speaks WSGI. paste.httpserver and cherrypy's wsgi server are the frontrunners for this purpose. Pylons is threadsafe, and paste.httpserver is rock solid, so I'm very happy with just a single paste.httpserver instance, but I can scale easily by adding more instances if need be.
Instead, I proxy from my front-end server to a standalone Mongrel-like webserver that speaks WSGI. paste.httpserver and cherrypy's wsgi server are the frontrunners for this purpose. Pylons is threadsafe, and paste.httpserver is rock solid, so I'm very happy with just a single paste.httpserver instance, but I can scale easily by adding more instances if need be.