I don't know how this is done in Gnome (Ubuntu), but in KDE (Kubuntu) we don't have almost any additional windows decoration to install from repos. The only one I found and even that was from PPA I think was Skulpture.
But ATM there are not even that much decorations for KDE4.
So it's even more strange why they are not ported.
Take a look at
KDE-look.
As you can see there are not many decos. But they should be ported, as the ability to change the look of your OS is for me one of the cornerstones of Linux.
