Do you have access to a modem which has the capability of interfacing to an electricity meter as well as having extra IO. Preferably one you have integrated to already.

If so what IO can you measure

We usually use other devices to do that interfacing. We do not currently use a modem to do that interfacing.
Of course, we can integrate, if you provide the hardware and protocols that we can use. There is usually a development fee associated with that, unless you talk large volumes.
Something in this line that we've already integrated is measuring up to 8 temperatures using ICPcon hardware.
This provides real time values, as well as Intrumentation Profile (basically a logger that logs it every 5 minutes. For this we do use a modem: the Siemens/Cinterion TC65).