I believe I have the exact answer to "Centos 6 Server has no GUI" but I don't see how to attach my answer to that thread.
I am running in Virtual Box on a Windows machine. When I changed my memory available from ½ Gb to 1 Gb , and my video memory to 24Mb, my installation script went from an interface reminiscent of MS-DOS in the 80's to a nice GUI installation, and my number of packages installed went from 200 and some to 1400 and some.
Apparently, the installation identifies what your box is capable of, and installs only what's appropriate. And doesn't tell you!
Regards, Rick