Is it completely outside the possibility of the architecture (?) of maxforlive for someone to create some sort of “master channel/multichannel” patch, that can be routed to seperate channels for modulation?
As far as I know, when you send midi between tracks/devices in Live, midi channel information is always lost. So if that is what you really, really need, I think you’re out of luck.
In my experience, though, it is often possible to find workarounds for Live’s peculiar way of handling midi between devices and tracks, and doing so without running into issues with latency or unpredictable behaviour. In the end, midi channels work like filters: they tell devices to pay attention to certain messages and to ignore others. Lacking midi channels, you can use other types of midi messages to send the info needed to do this filtering. 1 or 2 super basic Max4Live devices often do the trick.
There is no ‘standard’ workaround solution, though. It requires really thinking through your specific needs and limitations. Which can be annoying, especially if you feel it shouldn’t be necessary to have to do a workaround to begin with. Also, these solutions aren’t always very pretty.
So… if you have a specific use case in mind and aren’t too bummed out by the idea of hacky workarounds, feel free to share what it is you’re looking for. I’ll gladly try to see if I can help you on your way.