I use Github Pages for my status page too.

Not something I use for websites/web apps I develop for clients, but for my own irrelevant website, I go as far as to cheat and use the following:

    <img src="https://des.tination.server/img/1px.gif" 
         onload="statusOk()"
         onerror="statusDown()" 
         alt="">

    <script>

      function statusOk()
      {
        // do something involving green and check marks
      }

      function statusDown()
      {
        // do something involving red... and crosses
      }

    </script>

(Obviously you have to prevent caching)