I think that calling self.OnInit should be done *after* PostCreate is called. Otherwise calling any wx methods on self will fail.
I took this from the TwoStageCreation on the wiki. If you are indeed correct, that page needs to be fixed as well.
Also, I think it would be nice that if both -p and -u were passed on the command line that the output of both the resource loading code and the new class code would be output in the same .py file.
That's not a bad idea, I'll look into it.
What do I need to do to actually submit those changes for the next release of wxPython?