aha!  sony releases a FREE UPGRADE to allow 50Hz framerates on the FS100:

Sony USA has just officially announced NEX-FS100U is “WorldCam” via a free firmware update. “WorldCam” is a term used to indicate that a camera has the necessary framerates to be used worldwide. Beyond using a camera worldwide, having a WorldCam camera is also helpful when a producer needs to acquire content to be broadcast primarily in another country which uses a different framerate.

 

The free firmware upgrade for the FS100 which makes it WorldCam improvements include:

 

 

1.  Added 50Hz recording system (PAL): 1920x1080 50p, 50i, 25p and 1280x720 50p.

2.  Camera Profile (camera settings can be saved to and loaded from a memory card).

3.  Additional 4x and 8x Expanded Focus magnification: (with user selectable focus area).

4.  Selectable ISO or GAIN sensitivity display.

5.  Selectable Focus indication in FEET or METERS (E-mount lens only).

6.  Selectable Shutter indication as EXPOSURE TIME or SHUTTER ANGLE.

7.  Added the following Aspect-Ratio markers: 2.35:1, 1.85:1 and 1.66:1.

8.  Display ON/OFF button enables Zebra and/or Histogram overlay onto video output.

9.  Compatible with the new A-Mount to E-Mount adaptor, model LA-EA2. One push Auto-IRIS and continuous 15-point, Phase-Detection Auto-Focus operation with most Alpha A-Mount lenses is available. Lens metadata is displayed onscreen and stored real-time to image file.