The question is not “what should my PMO look like?”. Today’s question is “How do I build it?” If you treat your PMO like you should with any other project, you will be successful. A good requirements gathering effort, stakeholder engagement, modelling and testing the solution and more. Easy. Here is one of my YouTube 1 minute videos on the subject.
[embedyt] https://www.youtube.com/watch?v=_ZarQSd25cE[/embedyt]