Well, if this updated rumor is accurate, then the existing ATV2/3 already meets the description of this rumored set-top box. If this rumor is to believed, then it's simply a matter of getting the studios and/or local cable operators on-board with the idea of letting them stream TV shows within minutes of it airing, vs whatever delay the current iTunes TV show catalog has to work with. I guess I could see them sidestepping the major networks (CBS, ABC, etc.) directly if their previous discussions stalled and instead going to local cable operators and working with them instead. I suspect this will also involve a change to the buy-a-single-episode mentality, but will it require having a full subscription to the cable programming (paid to the cable operators, perhaps with Apple taking a cut), with the ATV serving as simply a better, more user-friendly cable box/DVR?
FWIW, I was a long-time TiVo user who switched to a Windows Media Center PC coupled with a SiliconDust HDHomeRun Prime network-based 3-tuner cablecard box. It works great, and it's even pretty iOS-friendly because I run Plex and MC-TVConverter, which allows me to (once the TV show has completely finished recording and MC-TVConverter has looked up the metadata for the show for Plex's benefit) watch the shows on an iPhone or iPad. I'd like to convince my wife to let me drastically scale back our cable package to a lifeline package (about $20) which just has the major networks.
I'd like to see Apple handle all of this hassle for us, but it doesn't look like that will happen. Even if they pull off some better deals, I could imagine that it will still involve a delay and will not have the local news stations. I hate the mass media news, but my wife still likes to watch it in the morning.