During my break from this project, the MIDI association announced a new transport supporting MIDI 2.0. The A2B bus is capable of transferring multiple channels of audio over a single UTP cable while also delivering power and additional data. This is interesting because it could replace the CAN bus used in this project while also providing audio streaming between nodes.

The full specs of this transport have not been published as I'm writing this, so some things are unclear. The announcement says a maximum of 17 nodes are supported with sub-buses, is that a hard limit? Can a sub-bus have sub-buses? The MIDI announcement says SPI will be used for MIDI, but none of the A2B transceivers have an SPI interface.

Anyway, I will continue using the CAN bus at least until the A2B transport is better defined.