The MIDI Manufacturers Association has a working group discussing the Standard MIDI File Version 2, or as some call it, the Standard MIDI 2.0 File (name is an undecided detail). Anyone interested in participating in developing the specification is invited to join the MMA.

This is just a comment on the midi standard "midi file format", it seem to me the most obvious flaw with todays use of MIDI is the range of channels possible to map. So either you will have to wrap the channel information with a "USB midi device layer" supporting multiple devices to be adressed in same song Or one would have to extend the number of channels in songs, but this would not be general and only work with synths supporting that type of mapping "well unless some sort of hardware split used to fork the chain".

I can see the USB midi device cable fabricant prefter the former

"I wrote a little midisequenser in javascript and a simple text format holder of data for it to save and load, it support sending/streming midi data/info over multiple devices and i guess that is how most DAWs work to"