I know MROS has nothing to do with ASIO, but there is no better fitting subforum.
MROS is an OS extension written by Karl Steinberg himself in the late 80’s for the Cubase releases on Atari ST. It is responsible for timing and routing MIDI events between applications and to hardware interfaces. It is the de-facto standard for using more than the one MIDI interface that is built into the Atari ST.
Since you list only VST and ASIO as APIs that can be licensed and there is obviously no commercial value left in the Atari ST, I would like to ask if you could release the API documentation for MROS. This would allow enthusiasts to breathe new life into their old hardware.