Joined: 11 April 2013
this sounds like a project I am currently working on...
For most electricity suppliers (Eon being one of them) they can provide what is called an IHD (in house display) to allow their customers to monitor their usage.
It receives data from the smart meter and displays it in a user friendly way, however this is usually the limit of its abilities; but it can serve as a good stepping stone to take the data received from the meter further to enable it to have the interoperability with phones or tablets (a good app could be written to address the features you want to cover such as being able to contact the supplier)
was this along the lines of what you were thinking of?
If you were more interested in m2m, I know of another system that uses this method for transmitting meter readings from water meters over GPRS where the data can be viewed through a web portal.
id be happy to provide more details or collaborate if I can be of any help..