Wow!

I don't know what I could possibly add after your post, Nick--you've got it ALL covered!

I'd vote for your choices of Hugh Grant as Coverdale, William Hurt as Hollingsworth (definitely got the powerful/threatening thing going on), and Sigourney Weaver as Zenobia. I still like Winona Ryder as Priscilla, though; she's wispy.

This book read like a movie. There are very few scenes I cannot imagine translating well to film. As far as Coverdale's narration, I kept thinking of that film about Beethoven from a few years back, "Immortal Beloved." A very different story, but, as in "Blithedale," there were mysterious elements that were slowly revealed by the narrator as the story progressed, and the ending was also somewhat ambigious.