Recently did several test with anamorphic shooting on the GH2. Tried 2 lenses. The Sankor 16C and the Icso Kiptar 2X. Kiptar is very sharp, but big and harder to get close focus. Sankor 16C is a great little lens. Paired it together with a Helios 58mm and Canon FD 50mm. Very happy with this result:
http://vimeo.com/37423237
http://vimeo.com/37423237