The 14-42mm panny lens works with IS, It's very light and image quality is average. Its' also small so filters are inexpensive and somewhat disposable. The IS has to be triggered from the camera, there is no hardware switch on lens so IS won't work on the BlackMagic Pocket camera, but does on the Panny cams.
I haven't tried the 14-140 yet. Will soon as have a new MR which will carry more weight. Probably be 1-3 weeks on that depending on free time and weather....
The RC shutter looks interesting, but the data rate on GH3 is so low, sd cards can hold lots of hours of video, so I just start the recording at take off and for the couple times I've experimented with stills, I just set it to start clicking away at take off and keep a handful of shots and toss the rest.
If I can ever figure out how to use my extra channels on my Futaba 8fg, I might try something like the RC Shutter. It looks like you set gh3 to take either video or stills at take off then the switches will trigger only a still(s) or video, depending on mode. Is that correct? It would be nice to grab a still in the middle of taking video, which you can do on the GH3 when hand holding it.