I just published on github (https://github.com/gtortone/MySensors-Efergy-e2) my last work about integration of Efergy e2 power meter with MySensors. The Efergy e2 electricity monitor (http://efergy.com/it/products/electricity-monitors/e2-classic) provides a sensor that wirelessly sends information about the amount of electricity you are using to the display monitor. The monitor converts this into kilowatt-hours.
This sketch use a JeeNode v5 (http://jeelabs.net/projects/hardware/wiki/JeeNode) equipped with 433/868 MHz RFM12B module (www.hoperf.com/upload/rf/RFM12B.pdf) configured in OOK mode to capture wireless data (on pin D3) and forward it through NRF24L01+ with MySensors library.
Comments and suggestions are very welcome !
p.s. photos will be published soon !