I'm trying to investigate custard more, just because my favorite vape is: Space Jam's Eclipse - which is a sweet tobacco mixed with vanilla...making it sort of like a custard. Also, I just got a bottle of: Ripe Vines VCT (vanilla/custard/tobacco) and it's pretty amazing if you're open to something in the same vein- though I can't taste the tobacco as much on this one. It's more of a straight custard/dessert to me.
And Space Jam also has an actual fruit custard one that I've been tempted to try, and I finally just ordered it on a whim and tried it this week: Starship 1 - "is a vanilla custard topped with fresh kiwi with a slightly sweet undertone." I've heard a lot about it, but it sounded nasty to me.....but don't let the kiwi thing throw you....it is awesome, and unlike anything else I've tried.
I would find a local shop near you to test these out though, since these, and most custards seem to be more pricey that a more simple juice. Good luck.