It is all over the blogs (Gigaom, Lightreading) and probably the newspapers... Cablelabs is researching 5 Gigabit over cable. This is something that was mentioned in an OECD Study I did 4 years ago. The problem isn't getting the bits on the cable. The problem is everything else, like getting rid of tv-channels. http://www.oecd.
org/dataoecd/49/8/40390735.pdf (page 18) has this to say about it.
With current technology it might be possible to send up to 5 Gigabit/s (upstream and downstream combined) over an HFC network if no analogue or digital TV-channels were broadcast and all bandwidth was used for data networks.
It becomes harder with the fact that the upstream channel is limited by the current filtering on the line to 120mbit up, shared over all users. So it would require a major rework of the entire plant to make good use of it. Add to this the 100-1000 users per cable headend and the real amount of bandwidth per household becomes more limited. So either you do very funky multicasting over IP (do remember that IP is encrypted per user, so that you can't see what your neighbour saw) or the network crashes if too many people watch tv at the same time. The cable network is very good at what it does now: Broadcast with a bit of IP. Going all IP with no broadcast however is a totally different ball game.
All in all I am still a happy user of UPC Docsis 3, I am still a happy supporter of FTTH for all, I am still waiting for a good FTTH offer to my home and I still await any great new technological developments on any network.... This just wasn't it, but unfortunately journo's will parrot eachother for days and consultants will parrot it for months and lobbyist will say it for years... (but now you know better)