CLI and GUI Question
 

Is it possible to build several systems that have only the CLI (no graphic user interface at all), then GUI have access to those systems via a seperate system that has the GUI installed?

If so, how and what are my risks?

I'm trying something for work and need to let the guys upstairs know before we move forward.

Yes, you can. X has networking built right in. This manpage has some (but not lots) of info on the subject:
http://www.die.net/doc/linux/man/man1/xserver.1.html

To tell the truth, I have found the documentation for this task to be sadly lacking...

I don't think security is very tight for remote X. So: do not make this available over the internet (unless you have a VPN or something), but if it is only vailable to a private LAN then the risks are less.