Many of you have probably notice that, as of late, compiz-9999.ebuild has been failing to build. This is because they have introduced the ability to compile for KDE4.0. Therefor, the current compiz-9999.ebuild has to be updated to include a KDE4 USE flag. I have attached the new compiz-9999.ebuild I got from the Gentoo forums here
Download the attached file, unzip it and copy the compiz-9999.ebuild file to /usr/portage/local/layman/sabayon/x11-wm/compiz
Open up a root
konsole and change directory (cd /usr/portage/local/layman/sabayon/x11-wm/compiz
Type ebuild compiz-9999.ebuild digest
Remember to make sure that the KDE4 use flag is not enabled unless you are compiling for KDE4.0.
(e.g. USE="-kde4" emerge =compiz-9999
All the best