I measured mine at home, and it uses 3W, either off or on, makes no difference.
As for alternatives... The university I work at has kept it's analog, and comcast has said it will keep it that way since it didn't want to pay for a box to go in EVERY dorm room, and in many of the classrooms, and other spaces.
That said, that would have amounted to well over 4000 boxes. The campus also handles all it's own distribution... so really, all they had to do is keep giving us analog. So, we got to keep our standalone analog feed while the rest of the city got moved over to digital. I'm guessing they split off our signal before any of the injections they do for cable modems, HD, etc, so they don't have to worry about clobbering the analog frequencies with stuff they've repurposed those frequencies for.
That said, your need is rather small... so I can't imagine Comcast is going to cave on this issue. I'd get them to cover the cost of the boxes, and just double sided tape the things to the side/back of the TV, and use the IR extender that comes with them. Power is going to be your biggest headache, since they use a wall-wort. =/