I am not aware of any notable political cluster that combines the two.

I suspect there is a reason for that. Namely maintaining high conscientiousness on a group level requires a common set of social assumptions and punishing defectors. Both of which are hard to do if you constantly have new people (especially from different cultures) coming to your society. I suspect the only groups that successfully combine openness and conscientiousness are living in isolated locations where natural barriers limit the amount of outsiders without the people having to "get their hands dirty" by lowering openness.