Reading manuals actually pays off, heh. Here's a quick tip for Vectropy users that may not have stumbled upon this gem.
If you want to just get some quick inline XAML to put into a file you're working on (e.g. a window layout you're editing in Visual Studio), but don't want to create a whole new image resource in your application, you can just copy and paste from Vectropy. In addition to copying the objects inside the application itself, Vectropy also puts a XAML text version of your selection on the clipboard. Draw whatever quick items you want, select them, and copy them:
Then paste into any text editor you like. Instant inline XAML!