http://server-monitor.herokuapp.com/ is open-source (MIT), and use the Opa framework (also open-source, MIT). The Dropbox-as-a-Database is integrated in Opa by default.
116 karma · joined May 19, 2011
The source code is released on github with a delay of several days.
And some previous discussion: http://news.ycombinator.com/item?id=3858838