Matthias Shapiro has published some Silverlight and WPF XAML files for a couple of US maps.
In the comments of my Silverlight unemployment visualization, someone asked about where I got the US outline. I got it from theWikiCommons website which has an SVG (scalable vector graphics) version that I pulled into Adobe Illustrator and then exported as a XAML file using Mike Swanson’s Illustrator-to-XAML plugin. I realized this might not be possible for many people who don’t own Adobe Illustrator, so I did it myself for several files that are now available for download as XAML vector graphics maps of the US.