Not sure if this helps but couldn't you just use the status area for that? You can find status bar applets for almost anything including desktop shortcuts (like phone) and media player, although I'm not sure that (as yet) the media player applet actually controls the media player or whether it just shows current song info.

Obviously it does involve an additional keypress to having a widget follow you from desktop-to-desktop.

One other thing is I've always had that 'bug' which replicates pre-installed apps, but what that means is I can have the same app on more than one desktop. There is also a hack you can do to enable multiple instances of applications.

D4rKlar