Tweetz-Desktop
Desktop Twitter client written in WPF
See http://mike-ward.net/tweetz for more information.
In this fork in the directory Transparent-Version I compiled different versions with different transparency percentage... i don't really have the time to add it as feature for the moment The _xx correspond to the transparency value example tweetz_45.exe have 45% transparency
To build your version
Just add "WindowStyle="None" AllowsTransparency="True" Opacity="0.40">" in MainWindow.xaml at line 21
;)