WPF/C#: WPF Path Maker Tool/Sample?
Jesema is another one that might be helpful for you:
http://marlongrech.wordpress.com/jasema/
If you want something where you can draw stuff inside a canvas, there's livegeometry
http://livegeometry.codeplex.com/
but that one has the path data abstracted away (that's more similar to your draw tools example).
Hope those help!
I know this question is quite old, but I found that Inkscape supports save to XAML.
See this article: http://www.software-architects.com/devblog/2008/01/13/Graphic-In-XAML-And-WPF