XAML exporters for several design applications

Microsoft Expression Graphic Designer [1] is one application which exports designs to XAML ready to be imported into Expression Interactive Designer, but there are others.

Mike Swanson, Technical Evangelist, has written a plug-in for Adobe Illustrator called AI->XAML [2] that exports designs to a XAML file.

If you're interested in a 3D modeling application which exports 3D assets to a XAML file then take a look at the post on this blog about ZAM 3D. [3]

Also, Thomas Goddard has written and released a freely-available plug-in [4] for Maya that exports model and texture data to XAML.

Daniel Lehenbauer has written a Xaml Export Script for Blender and his blog post features a rather fetching 3D model of Steve Ballmer!

[1] https://www.microsoft.com/downloads/details.aspx?FamilyId=ECD88D39-B9FC-4816-8DAE-60444B7C81E7&displaylang=en
[2] https://www.mikeswanson.com/XAMLExport
[3] https://blogs.msdn.com/expression/archive/2006/01/24/517169.aspx
[4] https://www.highend3d.com/maya/downloads/tools/3d_converters/3782.html
[5] https://blogs.msdn.com/danlehen/archive/2006/01/14/513012.aspx