Yeah, Luts had quite a few vampires, both male and female sculpts. All of their limited elves came with extra dreaming/sleeping vampire heads. And basic Shiwoo and Dark Elf Soo also had optional dreaming vampire heads in their parts section. There was also one or two limited Juri or Nanuri heads that were vampires, too. Oh, and their Lu Wen sculpt also had a dreaming vampire head.
So that's:
elf El
elf Lishe
elf Shiwoo
basic Shiwoo
elf Chiwoo
elf Yder
Dark elf Soo
Lu Wen
Nanuri 2007 (elf Moon vampire, I think)
Also, their Breakaway (and/or WooSoo) probably had vamp dreaming heads? As I don't own one, I can't say for certain, however. Unfortunately, Luts removed all their limited elves from their Delf page awhile ago. So no reference there, anymore.
Am I missing anyone?
Oh yeah! Fairyland also used to sell a Moon dreaming vampire head with their Feeple70 bodies, which is a sculpt originally released with Luts and fits on Delf bodies nicely. Could be that one, too.
Keep in mind that many of these sculpts sold secondhand have had their eyes modded open, too. So if it's an open-eyed sculpt, might just be modded.
Soooo ... does she have a pic of the doll, by chance? That would probably help to narrow it down a bit. lol