Interesting thread.
Moving away from Cujo...
I remember having a conversation with Stu at Betts about the Grant Limited Ed of Prime Evil. He described that as 'undervalued' given the fact that it's absolutely gorgeous. Perhaps, I ventured, it's the fact that it's a book of short stories. Having said that, Quietly Now, Book of the Dead and I am Legend are books of short stories and can command similar prices to Prime Evil....despite the fact that the production values on PE were much higher.