In Debian, I could install the x-window-system-core package, which would install an x server, and some programs that would make it work, like startx, etc.
There is no equivalent in Gentoo, as ebuilds like xorg-x11 install things like twm, and xterm, along with it. An ebuild like xorg-x11-core should be created that only includes the very very basic things needed to have an x server up, because most people will install their own window managers and xterm emulators anyways.
Steps to Reproduce:
1. Install xorg-x11
Installs a much bloated package
Install only the base x server
This is the same issue as with kde .. Gentoo takes the source packages so everything gets installed. Do you think a DO_NOT_COMPILE like in kde would be enough?
no, it would not. We played with the idea of splitting up X, but it's just not possible without a major headache. Debian, RH, and the binary distros can do this, because they compile the entire X and then just split the *binaries* into different debs/rpms. As a source based distro, we can't, I'm sorry. I've spent 6 months of my life trying to do this, and it's just too much of a hassle to do.
Now, for the good news. The Debrix project is what will come to the forefront for the next xorg-x11 release. Google debrix and you'll see how much better things will get.
As for xterm, it already _is_ a separate package -- xorg-x11 does not install the xterm binary.