This page is from the Trefach Campsite web site and contains amongst other things a panorama of the view from Carn Meini (the page calls it Caermeini or Carn-Meynen depending on the mood of the author!).
This is by no means an excellent example of a panorama, but it’s the only one of Carn Meini I’m aware of. Java support is necessary if you want to see the view.