I can confirm, Marecek found something similar to this. It was nearly the same as the 'grenadeghost' thing, but instead of only nades - you were also able to kill with guns.
I do think there are many more possibilities. New 'partly' godmodes could be discovered.
Like the one mentioned above, it's possible, but not really done properly yet as far as I know.
I also remember accidentally occurring a partly 'godmode'.
I do not have any proof of myself finding this and I have never found it again, so you don't have to believe me.
I was messing around in a vc-dedicated server with my friend. I decided to just nop out some random stuff and see what would happen: after I nopped a whole shitload of things: nothing it seemed.
When we started fooling around and shooting each other we noticed something weird.
I kept on killing him and he was asking: "Why you don't die?"
Well, I answered: "Because you don't shoot!"
So we checked out. I told him to stand in front of me, aim at my head and just shoot until I would die.
He was in front of me, but all he did was reloading, I didn't see any shooting at all.
But he really was shooting me! I was like 'yay' this is cool and I told him to switch back to normal gun.
Unfortunately, he just killed me with it, same with knife, and all other guns.
However: he wasn't able to kill me with his handgun. He could shoot me in the head until he ran out of bullets, but I didn't lose even the smallest bit of health.
My conclusion was there was something wrong with his weap.txt and he screwed up the handguns. To make sure he left the game, deleted his edited weaptxt.CBF file he was using and rejoined.
And still, he wasn't able to kill me with his handgun!
Well, I tried writing down all the things I nopped out, but no effect.
Still don't know why; hope you like my story though!
I might give it another shot if I find myself being bored.
But I don't really know if it's worth the effort.