I put this here rather than help as it's simple curiosity rather than needing to know for any real reason. I'd like to see if anyone knows, otherwise I'll just try it and find out.
Is it possible for a sim to be both a plant sim AND a vampire? If so I'm guessing they don't last long. On a related note, does being in a greenhouse or under the sun lamp do the same thing to vampires that being out in the daylight does?

Pretty much any hybrid you can think of can exist, except for a few (most impossible ones involving bigfoot or servos).

Vampire-Plant sims, with the excessive use of the heat lamp, can live easily. It doesn't count as sunlight because it's artificial, I suppose. I don't know. Read up on vampire mythos and myths about the sun or something.

Now, vampire-werewolves? That's when you get to irritating.

Well, that also answers about the heat lamp. I know servos and bigfoot are impossible as sims can't become them (and anyway I only have EPs through Seasons - though AL is on the way.)
I think it would be a bit funny to have a zombie-vampire-werewolf-plantsim-witch who also happens to be half alien.
I don't think servos should be able to be other supernaturals at all as they are robots, not living.

Servos can be vampires and werewolves, but that's it.

Servos can be vampires? I suppose vampires reproduce sexually, too.

ETA: I'm imagining a servo vampire breast-feeding her baby - now, there's a view.

Yeah the eye goes red and they have fangs. I have no idea. Really. But there you are.

I once had a vampire-werewolf-(plantsim?)-alien-zombie sim (that was before AL, so no wizard). Not the most successful combo, though, and I'm not entirely sure how it worked for the sim, as it was a rather messed-up creature...

I think he servo can be a witch, too.

In some circles, combo creatures are called Black Sheep. I've not yet made one with all possible combinations (keep meaning to), but I've had vampire plantsims. They're really not much more difficult to deal with than vampires alone, but it's rather sad that they can't ever enjoy the sun.

Vampires do reproduce sexually. Just ask Aurora Fleurada and her three children.

I've had a servo become a witch, but that's it for combined creatures, but yes the OWBC challenge on Boolprop does come with a side challenge to create a full mix of creatures called a black sheep. Most servo defaults come with a vampire and I think a werewolf state if you check them out.

If there's a thing I can't stand about this new vamp "lore" everyone seems to be spreading around like a bad std, it's this: they reproduce sexually. What the hell is that?

Am I the only one that still remembers that vampires are undead, a step away from zombies? As in "dead", but not quite so - meaning, a chunk of animated dead flesh?

Now I'm only waiting until someone destroys the myth completely by implying that they don't actually need to suck blood either, cause there's some... Wait, that already happened too.
I'm gonna watch me some Buffy today. I need a fix. Poof! Out you go, you dirty, demonic creature of the night!

Don't watch Angel though, I seem to recall vampire babymaking there too. XD

From what I understand, the entire point of Sims 2 is to make babies. Therefore...vampire babies.

Angel making a baby was a nasty demonic plot - a one time occurrence. And Angel isn't your usual vamp anyway. Now, had Spike produced an offspring - fruit of his loins, that is, not his fangs - that would have been sexual reproduction of vamps. And what a pretty bleached baby that would have been!
From what I understand, that can be done in TS3 too - vamps reproduce and kids have hair styles genetically transmitted from one generation to the next. Until one of those generations finds a mirror and changes their genetic coding.
A world of magic, no doubt!