These ebuilds come from https://git.overlays.gentoo.org/gitweb/?p=proj/xen.git;a=summary.
If you have some problems, go to the official site first.
xen-tools : Xend daemon and tools ( http://xen.org/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a xen
For Paludis use this rsync : rsync://gentoo.zugaina.org/xen-portage
If you have a problem : ycarus(-at-)zugaina.org