I'm setting up a headless server, but I still want to be able to run X apps on it - I'll just use X over ssh to display it on my desktop. Or I'll use tightvnc's server to run it on the server, and krdc or tightvnc to view it from another box. Like KDE's split builds, I was looking for a way to just install the client without the server to reduce build time, disk usage, and rebuilds due to patches in the server that don't affect the client. This server is not an NFS server with hundreds of GB of disk space, it's a mail/bind server with a small, old disk, large enough to run X-based text editors, but the less I need to (re)build on the machine, the better. (Of course, I'm not installing KDE there, either.) Reproducible: Always
I think xorg-server with USE="-xorg -dmx -kdrive minimal" gives you that.
In this case there is nothing additional to install. You just emerge the apps you need and they will pull in the needed client libraries. There is no need for a daemon running on the server in this case so there is nothing special to install either.
