During my holidays I wrote a little two parts piece called MulleHostCheck. I used MenuMeters as a starting place to code up something which shows the status of a configurable number of hosts, with cool blue LEDs in the status bar :)
 offline |
 online |
 Configuration |
If you like you can download the project. It's not polished, even has some cosmetic bugs, it doesn't have a unique icon. No homepage for it and no documentation. Realistically, I wont spend any more time on this.
It might be that you need MenuMeters installed to run this, because MenuMeters comes with a MenuCrack thingy, which could be neccessary.