Are you only looking for modern genre-fic examples? If not, Le Fanu's "Carmilla" is pretty much the great-grandmother of English-language lesbian vampire stories; you could make a pretty good case for Geraldine in Coleridge's Christabel being a precursor of this type, too. (Heck, you could probably dedicate an entire panel to lesbian vampires alone, there's such a wealth of examples ranging from Victorian literature to modern queer erotica...)