In this tutorial, Peter Kuhn discusses creating a theme pack from Silverlight theme files.
Source: Mister Goodcat
Some time ago Microsoft released the four Silverlight Application Themes Jet Pack, Accent Color, Windows 7 and Cosmopolitan. You can find that download here. The Themes are provided as comfortable installers and integrate as new templates into Visual Studio. The drawback of the loose style XAML files the themes come as is that they cannot be easily used as Toolkit compatible theme packs, which makes dynamic switching of themes difficult, for example. It also requires more effort than necessary to apply the styles in an already existing project. I decided to convert the themes into theme packs, but that turned out to be harder than expected. Read on for a step-by-step guide and an online demo with full source.