I find the @maddox solution quite a clever approach ... it basically let's Channels manager the streams as individual tuners. I tried it out with setting up 6 single channel sources and recorded 4 channels simultaneously...it worked great. The Pluto-for-Channels web screen is a nice touch.
It would be nice if it was handled similarly to HD Homerun (4 tuners), where we could just indicate the number of tuners/streams at 12 (or whatever) and the proxy would manage the tuners/streams...that would allow a single channel lineup. The interface to manager the tuners is already built into Channels, so it seems like the new proxy just needs to leverage that type of API to the proxy.
Looking forward to what's next on this evolution.

seems like mpeg-ts fixes it the commercial issue.