Here's a group I play now and then they are on my definite the "to keep" favorite list. I kind of consider them almost as one sim though so I'm going to pretend they fit the topic. They are connected.
I made them as adults vampires then aged them down to children in CAS. Not sure I will ever age them up in the game though. These kids are very loosely based off a creepy little 1960's movie Village of the Darned... had to make that word darned but it's not even rated PG that I know of so I guess I can say that here.
Their story is kind of static right now because I'm waiting on a mod that probably won't come until we have more supernaturals or potion effects ect to work with. I want something that will give them powers over others ... or telekinetic powers. I want them to have this as children though. I'm patient, I can wait. They do everything en masse.. which usually is some sort of skilling. They are all geniuses and have the same aspirations at the same times. Windenburg is a perfect setting for them.
I have changed their story from the movie in that in my head they have some sort of unknown powerful Sire (not sure he's a vamp). They live with their servant caretaker. I gave the poor guy the hates children and squeamish trait so he's always uncomfortable or about to be. He cooks and cleans and lives outdoors lol.. he is often miserable. It's his duty to protect and serve them though and he will see it through.
Sim vampire children can go out in the sunlight... they also don't need "plasma", but they look suitably cool.

Psst people that have a problem with presenting too many just post more often :).