Golda's Kitchen has them listed at their online store. You can call ahead and find out if they have them in their retail store and if they don't you can order online and either have it delivered or held for pick up at the store.
Are you talking about precut flat sheets that fit a half-sheet pan? I bought a package at the McCall's Baker's Warehouse sale a few years ago. They are only open to the public for a few weeks in Nov/Dec. Check the main McCall's and ask if they can get it in for you.