I doubt that powerline network that dishis building-in to its receivers is going to be fast enough to allow the transfer of recorded content over a powerline network without considerable lag (maybe 5-10 minutes before you can really start to watch a show on a remote box and have enohbuffered to be able to skip commericials).
I don't know about that one. I work for a BPL company, and we run up to and over 85Mbps over in house powerlines. If dish really wanted to make it work, it would.