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.
The script is below. Update July 28, 2010: In part of archiving this from the Vagary, I've moved the code to pastebin.com Please find it here and enjoy
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.