So, when a tuner is used, it's recording... even if Live. So, if you have to do "tuner math" to figure out, for example, how many people can actually watch Live TV at the same time. Basic logic says if you have 2 tuners, the most you can have is 2. There are a lot of reasons why you can't get 2 though depending on whether or not the Tablo needs to use a tuner for other processing.
But the point here is that for different people to watch Live TV at different "resolutions", that would mean dedicated tuners (different file streams and not necessarily based on "viewer" but on "viewer" and/or "device"). Now I can't tell you the answer to this... if on the Tablo today and two people (assume local net) are watching the same channel "Live TV" do they just get pointers off the same m3u until they diverge enough (e.g. somebody pausing for a really long time)?
The answer to that question would help to make an absolute determination about what can and cannot be done on the Tablo with today's software.