I guess you didn't check out the post I linked(probably because it somehow send to the completely wrong page for some reason, here's another one that will hopefully work,
post #7540 in the thread) then which has a 10 bit version as well as the hevc one. I've been making 10 bit encodes of JAV for years. I am the only one as far as I know though. Vitreous thought about doing some but I don't know if he actually did.
As for why you don't see it much outside of anime is that the gain is much higher the less complex the picture is so you'll see a lot more gain with drawn cartoons than with a real world video and it takes longer to encode(it used to be twice as much, but I think that dropped quite a bit, I'd need to test it again).
Edit: And before you say there's no 3D rip of JAV movies:
https://www.akiba-online.com/thread...-navigator-ddt349-2d-3d.1074267/#post-2077799
As for why that's really not popular, most, if not all players don't support it apparently. I've had a guy or two test it and for it to work, some TV setting had to be changed for it to be properly viewable.
I sure do love messing around with encoding stuff