After getting inspired by this Reddit thread, I finally started playing around with GeekTool. This is what I came up with. I'm pretty happy with the design and layout, but my router ping scripts bugged me when I was not at work. Fortunately GeekTool 3.0 supports AppleScript, so a solution wasn't far off. Check out my demo, below.
Since it uses an idle handler, you need to save it as an application with the "Stay open" option checked. I did my script testing and debugging before I put the handler in there, just to simplify things.
Remember to replace "HOST.DOMAIN.COM" on line 27 with the hostname of a host on your network that is only internally-accessable.
Update Nov, 7 2009: You can grab the Geeklets from here, if you're so inclined.