Fair warning: Although some pages of the first chapter are almost identical to this doujin, the story is completely different. For one thing, the girl seems to be loli both in body and mind. For another... I don't think she's a vampire anymore.
Regardless, it looks fun, so I'm hoping some group picks it up.
For another... I don't think she's a vampire anymore.
Eh, but that's what made the whole thing stand out among other similar stories... Might still be good nonetheless, though, we can usually trust this author.
Vampire cats are reasonably common in folklore and legends, both in Japan and the west. One of the very first vampire novels (predating Dracula) was Carmilla, which featured a lesbian vampire turning into a cat form to feed on young women.