Hello,
i have testet Ubuntu 12.4 Lts with KDE Backports 4.9.2. http://www.kubuntu.org/news/kde-sc-4.9.2
After the last Fix from Mike it works with the X2go Nightly Builds. http://code.x2go.org/gitweb?p=x2goserver.git;a=commit;h=55d23d3c52f83f81bf98...
I have now no Kwin crashes after login!
Regards Mirco