Personally I find sound to be so integral to my video work Ive kind of dropped my eye off the ball for cross over cams.
I guess 5dmk3 is an excellent stills cam with adequate video, the GH3 is an adequate stills cam with quite good video (but no ND or sound)
Sony make a few cameras shaped like video cameras Sony "EA50" apparently these take stills but I cant imaging shooting a stills job on one!
Incedentally the EA50 video is not too good.. because it is line skipping from the higher stills resolution.
I only think we will have a proper cross over camera when the nikon D5 or canon equiv. simply shoot at 25 frames per second (raw normal stills!)
Oh.. one other option the Canon1dc does 4k video and good stills, personally I think it is over priced and with a mini HDMI, no sound and no ND just poorly conceived.
If you had an C100 and a 5d mk2 or eve mk1 you would probably be in a better position!