I have recently added drag and drop support for graphics in the ESRI Silverlight API to the ESRI Silverlight API Contrib library. The library has also been upgraded to ESRI Silverlight API Beta 2. Will soon upgrade it to RC. The drag & drop functionality can be added to specific graphics or to all the graphics in a graphics layer. Enabling drag and drop is real easy. Just call the ‘MakeDraggable(map)’ method on either a Graphic object or a GraphicsLayer object. ‘MakeDraggable’ is an extension method that takes a reference to the ESRI Silverlight API map control to do it’s magic. The return from the method call is an ‘IDisposable’. To stop the graphic or the graphics on the graphics layer from being draggable, just call ‘Dispose’ on the ‘IDisposable’ object returned above. The map remains entirely usable when the graphics are draggable, so no worries there.
I am also currently looking into adding custom drawing tools to the library that will have the map be pannable when drawing and allow adding new drawing tools like circle etc if needed. If you want to see some new interesting features added to the ESRI Silverlight API Contrib library, let me know 🙂