According to the Gnome release notes, sabayon is supposed to be included in Gnome, but it currently is not and there appears to be no ebuild at all for it.
there is a open bug about this
Gnome including sabayon depends on there being an ebuild for it. I assume that is what Gilles was mentioning about there already being a bug for this. That issue would block this issue.
yep, that's what I meant. Sorry for imprecision, I was recovering from my jet lag.
sabayon is in the overlay, and will be included when 2.16 goes into portage.