Hi @nburek.
I am Borja from eProsima.
I think that meeting you propose is actually a good and nedded idea.
We are part of the OFERA project and would like to participate on that common effort for design and implement such ROS 2 for microcontrollers.
Currently we are doing some effort to open a discussion on possible designs for a framework like this for microcontrollers.
If you want we can join to organice this virtual meeting.