So I've been at this course on Cisco CMTSs this week so I was thinking about how the typical DOCSIS setup might look in 5 or 10 years.
Everything will be DOCSIS. It seems to me the industry is really wasting a lot of money on SDV & VOD. It would make a lot more sense to just do everything via DOCSIS with IP video to the set top. So your typical cable system in the future might be something like 85 DOCSIS channels as one huge pipe to each node -- able to dynamically be used for a combination of voice, data & video. Building a tuner that can handle 85 channels at once might be a little too expensive even in 10 years so perhaps you'd do them in groups of 8 or 10 channels per service type. Video = 400mbit, Data & voice = 400mbit. Narrowcast video = 400mbit. That's only 30 channels.
Another advantage to this is building an IP aware network makes your delivery medium far less important. RFoG or FFTH, where needed, would work just as well as coax. It would make a smooth transition in the future.