Solved! Go to Solution.
Try to look in the silverlight API symbols gallery which will should work for the WPF API as it is also based on xaml (you may need to replce Key with Name). I guess the custom marker symbol will be most suitable to feet your needs.
Once you build your symbol with xaml you can do many cool staff in the UI.
The symbol gallery is located at:
http://resources.arcgis.com/en/help/silverlight-api/samples/SymbolGalleryWeb/start.htm
There is no build in solution as far as I know so yes, you need to create animation yourself. Note that if you are using AcceleratedGraphics symbols doesn't support Xaml Control templates and visual states. Check this, you might get something useful information from that and extent the solution to support flashing. If you do, please provide your experience here or in the blog.
You can select graphics but you need to provide Selected and Unselected states for the symbol and that is meaned for selection visualization but you could use that also but I wouldn't do that.