Wow that looks awesome, question, how did you build the covers? Was the silver an option or an image you used? And also how did you upload your wordmark with transparencies, cause when I upload my logo onto the book (.png interlaced) it flattens the transparency.
to build my books I choose: "General" then "Build Your Own" this will give you a blank pages. The cover is white by default. Then I just put my logo which was on white, on the cover. Can't upload transparencies. Metallic is Adoramapix's default for all covers so it makes white look metallic silver-ish.