The WSGI support for IronPython is definitely coming along. I'm confident that it can be made to work well. Loading the IronPython runtime statically has created a decent performance boost -- at least to the point where I could see using it in real applications.
I did run into a problem with the implementation of start_response(). We currently aren't supporting the third exec_info parameter which has something to do not resending the headers in an error situation. This is preventing the flup session middlewear from working, and since the OpenID client library requires a session, I'm looking into that next.