For those of you using openSUSE 11.2 of you, xserver packages with the backclear patches applied can be found in my obs repo:
http://download.opensuse.org/reposit...openSUSE_11.2/
You got it exatly right. It's that in-between section/line that I'm seeing. Also I checked out your screenshot and I get that too. I don't know if it has to do with compiz or the no-backfill patch.
When I change the compiz animation quality settings to "best" it's much more prominent than when I have it set to "fast".
Anyhow, I really like the new ubuntu theme so I'd rather use it with these minor annoyances than use a different one that would cover up these artifact related problems.