More servo channels

G’day mates :wink:
I’m working on gasoline octoplane (quadplane with 8 rotors - something like Porter). I’m using Cube as autopilot. Currently I use 12 output channels as primary flight controls (8 rotors + AETR). I would like to use 3 more channels for custom payload and another 3 for starter, choke and ignition switch.
Is there any software support for more then 14/16 channels? It might be UAVCAN, S-BUS or whatever as Cube has only 14 physical channels.
For example: S-BUS on Serial2 outputs Servos17-32.