Crazy thought but...
Does anyone know of the program called foobar2000? It's a media player that allows plugin support. One such plugin is called foo_panels_ui.dll. It can do allll sorts of things to the GUI of the program. One of the things it can do is manipulate vista glass. Vista glass is NOT built into foobar2000 at all, only in the plugin panels ui. It can be actived with $glass(x,y,w,h) or something like that.
Panels UI
So, perhaps through the add-ons feature of WLM (or the scripting engine?), a plugin could be made to achieve the glass effect you seem to want.
This may be helpful, I don't know:
Extend Glass Frame Into A WPF App
Just thinking. It would only work on vista machines obviously, but it would be cool ^_^.