I was recently given a commission for a cover to a romance novel. It's about lesbian vampires called nymphomites. The Myspace page for it can be found here. Caution, it does have sexual content in the excerpts from the book posted in the blog.
Here's my process for it so far:
The basic idea I had was for the two women to be embracing while the vampire glowed and the others lurked in the background eagerly waiting to join them. I cropped a pose of the vampire holding up the protagonist's leg while kissing/biting her neck. It takes place in central park so I had the city off in the background above the treeline.
I'm currently working on the colored version. I have Coraline playing in the background so I started looking up the original Dave McKean book and the merchandise and it's influenced my stylization a bit.