I am looking for suggestions for a good adapter for Canon EF lenses on the FS100.

What you want is the Metabones adapter. I have more information on it on my blog. www.gforcevideo.com and click
on the 'blog' button. It's the entry entitled:
'Metabones NEX to EF firmware'

I have the Metabones. Works perfectly fine. Nicely built and solid.

I concur.........

Have a look at this small review I did last week...
New Metabones ‘Speed Booster’ adapter | Blog e-vdh.be Productions (http://blog.e-vdh.be/?p=320)