Well, ponder no further — here is a Stage 4 Vampire Werewolf:
What a great vampire this guy is, right?
I really like how the background color for the Vampire and Werewolf skills contrast one another. Orange for werewolves, blue for vampires.
And, it's interesting to see how both skill lines take up even more space in the skills menu. It's like seeing the Emperor skill line show up for the first time.
It's really a shame that we are unable to utilize both curses in normal gameplay, as it will prevent you from casting Werewolf Transformation if you also have the Vampire skill line (though as a Vampire you will still benefit from the +15% stamina recovery for slotting Werewolf Transformation). As for hybrids, it would've been nice to have the stealth bonuses that Vampire gets on a Werewolf. I'd argue that although Vampire is clearly designed to be stealthy and Werewolf is designed to be brawny, Vampire is already quite brawny and Werewolf can use a bit more stealth.
Regardless, I hope this thread sates your curiosity for what we could've had!