The answer might be as simple no, but using Ubuntu Tweak I made the borders of my windows transparent as shown here:
However, the window buttons and window title are also transparent, making them look out of place. Can I make the close, minimise, and maximise buttons as well as the window title non-transparent?
This would be possible with Emerald (which is no longer maintained), but it is not possible with metacity/gnome-window-decorator/unity-window-decorator.
You can file a wishlist bug though.
Alternative:
There is a PPA that contains a fixed version of emerald (fixed as in - it fixes a segfault that some users got):
This PPA is for 11.04, so you have to download the .debs for 11.10:
(for 64bits or:)
(for 32bits)
For more info, see this Ubuntu Forums thread: http://ubuntuforums.org/showthread.php?p=11379530
If you design a theme yourself, you can do things like this in metacity version 2 themes.
Update:
Here is an example: http://mikegraydesign.com/files/metacity-theme-2.xml