Congrats! This is exacly what I was looking for for an energy meter project. 
In fact I was just looking for the case, but this will make me consider my design from scratch.
I don't know whats on your roadmap, but for my use case I would love to see some add-ons:
-220Vac to 5Vdc power supply, so that you can power the unit straight from the 220Vac
-Maybe a baseboard with an header interface capable of use regular shields already on the market.
- Or shield's/modules combining uSD card with either Xbee/ Bluetooth or Electric IMP.
Keep up the good work.
btw-It's not clear from the site, the dimensions of the kit. How many DIN RAIL units does it take. Looks like 5, but not shure.