My idea is to have a meta-device that takes pattern data from one track and copies it to another track, optionally including note+octave, instrument number, volume, panning, delay, command, and cmd parameters. This would enable, for example, to trigger several instruments with one note, ordo some wicked sidechaining effects or…
Disadvantages/problems could be: what if the destination track already has the maximum amount of notes, or maybe hearing sound from an empty track and wondering where the notes come from.
There won’t be tracks with empty notes, at least not if you want your stuff to be rendered as well, because empty tracks will remain silent if instruments are triggered in those tracks but not by notes inside that track.
The Midi Management tool allows you to chain instruments in a birds-eye view and to edit / record notes in multiple tracks for each of these chained instruments (if the multitrack edit button is enabled).
I don’t know what kind of wicked side-chain effect you had in mind for the other option.