State of low-power modes on BBB w/Debian & 3.8 kernel and related questions

After a little googling, it seems that it's hard to achieve the lowest theoretical power consumption on the BBB in sleep. As of November 2014, it seems the HDMI and LAN remain powered, and possibly the external DRAM is not put into a self-refresh mode. Does anyone know what the state of these things is in the latest 3.8 images? Would one need to use a more recent kernel for better performance?

In my situation, I never need LAN or HDMI, although I do use LAN during development. My device can be "off," as commanded by the user via a GPIO. I'd want that GPIO to be able to wake the BBB when it goes high (or low).

Is it possible to implement wake-on-LAN via a WiFi chip or USB dongle?

Finally, is it possible to sleep most of the board and main processor, but leave a PRU core running to monitor some ADC inputs, and then wake the rest of the system? What kind of power consumption could I expect to see in that mode?