Interesting thought. Powerline communications have been discussed for quite a while, but they tend to be horrible channels (old copper, long distances, bad shielding, etc.). So yes, I'd expect OFDM for the equalization and multipath (or 'echos' in this case) issues and heavy channel coding are required.
My main question regarding this topic is to figure out what would be necessary to create a test bed to try it out on? Obviously, we aren't going to stick the Rx/Tx port of the USRP into a wall socket :)