More info with video of the firmware.
http://www.newsshooter.com/2014/11/20/panasonic-gh4-v-log-picture-profile-spotted-in-the-wild/
quote from newsshoter
" By technical editor Matt Allard:
A GH4 on the Panasonic stand at the Inter BEE show in Tokyo today was running beta firmware with the V-Log picture profile. This Log profile is similar to the one in the much more expensive Varicam 35. This would be a very welcome enhancement for anyone trying to get the best possible image from the GH4, and a huge advantage for colourists trying to match the GH4 with other cameras.
I spoke to a Panasonic representative who told me that the V-Log Picture Profile was only being tested at the moment and isn’t confirmed for the next firmware release. Interestingly enough though I did run into a Japanese shooter who had V-Log operational on his GH4.
Lets hope that it is indeed scheduled to be included in Panasonic’s upcoming firmware update."