Well, it looks like our utility (PEPCO) is installing meters from "Silver Spring Networks".
I don't know the model for sure, but I saw one photo (from a local article) of a Focus AXR-SD meter.
The user who started this thread reporting his system didn't work at all after one of their meters was installed (same model), but I couldn't find anything else on them. I didn't see a resolution to his issue, or if the problem was caused by the removal of his coupler or not.
PEPCO's website says the meters use 900MHz and 2.4GHz to transmit their data back to the utility, so I'm hoping that means they are not sending signals on the powerline itself (and therefore shouldn't be interfering with my system).
Does anyone have any other information on their meters, and what (if any) interference they may cause with my X10 installation?