I decided to look at the way other people have specifically tackled John Steinbeck novels. As a collection, I can honestly say they, collectively are some of the worst covers I've looked at. A lot of the time they're going for a classic look, which I guess suits the literature, but they're quite simply, awful. The attempt at being radical on Viva Zarata looks really messy and the vibrant pink is a little garish. Others like the fantasy-style artwork for the pearl just evoke a really amateurish feel.
Below are some covers that I can't find a credit for, however they're really contemporary and really appropriate illustration techniques. It might be worth adopting something like this to however, it being special editiong, I might need to do things such as adding spot varnish or foil blocking to make it look mroe expensive and one-off-ish.. or collectible and desirable.