Hi,
I was also looking for an all day vape all the time.
And never found one...
But then I just picked the best (least annoying/least disgusting) flavor I've got (already have about 200 flavor concentrates/liquids) and forced myself to stick with it.
It will take some time, but in the end your body will just learn that whatever flavor your vape it that stuff that gives you the satisfying nic.
When you think about it it does make sense: Did you're first real cigarette tasted good? Of course no
But my body just learned that this disgusting, bad tasting smoke equals satisfaction.
But nevertheless I still trying new flavors once in a while.
Recently I mixed a very simple liquid, that does taste quite good (which is surprising considering how few ingredients it has):
Base + 4% Tobacco Absolute + 2% Ethyl Maltol.
Actually this is the nearest thing to a real cigarette I've discovered yet (House Of Liquid El Torro Liquids are also pretty close).