There's an RPM updater tool - can't think of it's name, perhaps called autorpm or something. Look in /etc for a config file. You can configure where it looks for updates so you can have one machine get them for real and the others just poll it. Newer versions have this thing called up2date which I have not played with. Presumably you can configure it similarly.

You could also cobble something together with a shell scripts.

The biggest ugly to watch for is X Windows as when it goes pear-shaped it likes to lock up the console. However, once that's sorted it stays stable. Most problems crop up during install anyway once installed rarely do issues occur. It is Linux, after all. :-)

Oh, if you aren't that familiar with NIS, go read up on it. I did it once for kicks and it was not something I would have figured out without a tutorial.

Wade.