Have you tried the stuff available from here
Paper-Papers.com Metallic Paper and Metallic Cardstock? Not sure what subjective standard you are looking for, but the few times I have used the Silver, Lustre, and Crystal card stock from there have been adequate.
I tried some of the Silhouette printable silver foil, but that did not work out very good. It has a clear plastic film over silver colored paper and is backed by a white layer. The printing goes on the clear film which likes to separate from the silver layer.