Well, I have searched a bit, and it seems that there are Sega Genesis emulators for PC that indeed support Sega Pico roms. I suppose that these are good news
In any case... let's speak about this topic once you have finished your work in the Xtras emulator. That project is more important!!
In the meanwhile, I will try to study these emulators and see if the Sega Pico controller code is clear and it seems easy to identify. Maybe this can help in a future port.
Thank you for all your work, Madmab!!