I’ve found an easier way to do offsets (shadow layers, mats) in Inkscape, using my old friend the Paint Bucket Tool. Video and written steps included.
Update: Cricut people please see this updated post. Silhouette Studio Designer Edition Plus or Business Edition users now have a Conical Warp feature to curve text and images automatically. I have shared these files in various forums over the years but never got around to putting them on my blog. If you are cutting vinyl for a standard 16 oz double wall tumbler then this template will let you curve