Jim Martin spent the weekend creating a great plug-in for Graffiti that makes it super simple to insert streaming Silverlight media into your posts. The download and usage instructions are here.
Note that this should be considered a beta/demo/(however you say not officially supported).
I should also not that because of that installing this plug-in, similar to the Silverlight photos plug-in that Kevin created, requires manually dropping the DLL onto your sites BIN directory. The shortcut to doing this without server access is to use the GraffitiCMS file uploader: In Graffiti, as an admin, you can do this with Site Options > Utilities > File Browser. Open the Bin directory and click Add Files.