I have successfully integrated TED, The Energy detective, into Mango. I have been using TED for over a year to track energy data in an effort to reduce electrical consumption and cost. The consumption has been reduced by over 15% but the cost has stayed the same since my utility keeps raising rates. Overall I have avoided the increased expenditure by reducing consumption.
TED will output an XML file (not well known or documented) when commanded assuming you have the USB data option enabled. TEDService must be running but their "Footprints" software does not have to be to get the XML file. You can use the command "dashboarddata" to get the XML output.
On the Mango side I used the HTTP Retreiver as a data source. In the URL I used "localhost:8085/dashboarddata" (TED default port is 9090). In my case TED is on the same computer as Mango so I used localhost. You could use any computer on your LAN as long as your firewall setting are correct and use that computers static IP. Then in the Value RegEx field I used <DlrMtd>(.*?)</DlrMtd> to parse the XML file for specific data. In this example this returns the value for Dollars Spent Month-To-Date.
See my public page at http://mikeshouse.homedns.org
The 1-wire temp sensors are sitting on my desk so all the data is the same. I need to get around to running the Cat5 cable to the field devices.