Check out http://www.usnap.org
From the home page:
Introducing the U-SNAP Alliance
The term U-SNAP is an acronym for Utility Smart Network Access Port, a simple, yet cost effective solution that enables any HAN (Home Area Network) standard, present and future, to use any vendor's Smart Meter as a gateway into the home, without adding additional hardware in the meter. By providing industry with a protocol independent serial interface, it is possible to extend the Smart Grid directly to energy aware consumer products.
This looks like a communications interface into the CPU being defined for the "green home" stuff. In theory, it allows "Smart Stuff" (grids, meters, thermostats, appliances, etc) to be built now and the physical communications protocol (ZigBee, ZWave, PLC, etc) to be decided later.
Contrary to you, I like the idea of the JTAG interface being in a separate device.
It allows the Plug to be as small as possible in it's deployed form (like plugged in at various spots in my house) while letting any Plug be a development platform by connecting a cable. IMHO, since they moved the SD card to the main Plug body, it is a better solution than the Iconic's. YMMV.