Well, it's been just over two years since I asked the question, and I'm happy to report that we finally signed up to get solar panels. We signed a Power Purchase Agreement (PPA) with SolarCity.
Put simply, we pay nothing for the panels (which they own and are responsible for maintaining for the duration of the 20-year agreement), and we agree to purchase all of the power produced by those panels - at a lower rate (per kWh) than our local utility charges. There are no monthly fees - we only get billed by the kWh.
It will be 3-4 months before the system is installed, so I don't have all of the details of inverter models, etc.
It will be a grid-tied system - where the excess power is sent back through the meter to the utility, which goes to reduce the total amount we pull from the utility across the whole month.
We will not have any storage batteries in this setup. They expect it to produce about 70% of our power needs - on average - resulting in about $40 savings in our monthly electric bill at first. The panels will also help reduce the heat load on our house (by intercepting the solar energy before it gets absorbed by our roof), which will save us a little more, too.
I was incorrect in what I had said two years ago regarding the monitoring. SolarCity is only monitoring the output of the panels (the inverters use wireless communication - I think ZigBee, but I'm not 100% sure - to communicate with the "gateway", which then plugs into my Internet connection to upload the data to their monitoring system). They are not monitoring power consumption of my house or using the power grid for data transmission.
I already have a smartmeter from my utility (although they will be replacing it with a new one capable of net-metering when the panels are installed). So far, I haven't noticed any problems with my X10 system from the smartmeter - which has been in place and sending data to the utility for well over a year now.
I'm really hoping the inverters won't cause any problems with my X10 system - but I won't be able to know for sure until the panels are installed and running. If there are issues, I probably won't be able to fix them.
If there are any forum members who have a setup from SolarCity and X10, please let me know what your experience has been.
Thanks.
--Noam