Here is the initial release of the Blender to XAML python export script.

Blender is a awesome free Open source 3D Animation & Modelling platform, download it and give it a try.

PURPOSE:
    To allow rudimentary XAML export capabilities.  Currently the goal is to
    support just the geometry,Solid Materials & lights.
    Texture & Animation will be in the next version.

IMPORTANT:
    You probably need the FULL python installation (2.3) to run this script.
    If you have problems, get the python installation from
    http://www.python.org , make sure also to set the 'PYTHONPATH' variable



 USAGE:
   Select one or more objects and execute this script (ALT+P)
   Be Sure to select a Camera & Light :) if "Exported Selected" is on.
   Everything that CAN be exported, will be written to the export file.
   You can change the export filename by entering the path and filename
   in the dialog.  If you do not enter a path, the export file will
   appear in your blender directory.

   The Color Sliders on the top represent the Ambient Light in the "World"

LIMITATIONS:
    Your mesh "M U S T" be triangulated before you execute this script.
    If you don't there will be holes in your mesh.
    Only exports triangular meshes,spot/point light,materials & camera currently.

    Texture coordinates & Normals are NOT be exported. 

NOTES:
    If you would like to contribute, or make modifications, send your mods
    to me and I will incorporate them into the next release which I am currently working on
    for everyone to enjoy.
    Please don't distribute modified copies of this file without contacting me
    first!

Here are some of the screenshots of the XAML Export script in action. I truned off the OSA(AA) to compare the rendering in Avalon (WinFX) to that in OpenGL based blender.