Not an expert, but at this time I don't think it's possible. Whilst it would be brilliant to look at it, I question the practicality. But hey, we all know how much looks matter to people! *looks at all the skinning threads*
This kind of windows-handling is going to appear, apparently, in Windows Longhorn as part of the ALT+TAB remake. Perhaps when that comes as standard it would be more practical to start thinking of this. As I said though, I'm no expert, but I doubt this is easy to incorporate, if not impossible altogether.
Regards,
