With KDE 4.11 beginning to support Wayland through KWin window manager changes, a Gentoo maintainer is already readying the support to use Wayland/Weston in conjunction with KDE rather than X11.
Wayland has already been found in Portage for some time and with the KWin 4.11 Beta 1 + KWin master there is now a Gentoo USE flag for Wayland. Right now it's possible to successfully build KWin-for-Wayland under Gentoo, but there's still some work left. AMong the steps left is packaging the Weston compositor for Wayland and adding a Wayland build option for the KDE start script (startkde) to use Wayland/Weston.
The aim is by KDE SC 4.11 in August is to be able to easily play with KDE on Wayland using Gentoo Linux by simply setting the appropriate USE flag for Portage.
More details can be found in this blog post.