Indeed, I put together a gpu mate desktop Raspbian Stretch pi3 kernel version with Overlay, AUFS, and the vc4 core bug fix.
https://sourceforge.net/projects/microm ... -pi/files/
(there is still that flash & gpu enabled VLC plug-in bug that requires restarting midori once)
> disable swap
not a good idea for users given the ram drive fills quickly, but I simply moved the swap file into a user partition
(The OS / and /boot is read-only)
> mount some files in ram disk (logs & cie)
already done, keep in mind you'll need to modify several processes (mostly systemd related)
> make SD card read-only
While the program is compiled in this OS, it doesn't really allow easy updates
You could easily modify the scripts for your setup with:
1. remount the os in RW mode
2. cp -R /home/pi /root/pi
3. apt-get remove purge dphys-swapfile
4. unmount /home
5. mv /root/pi /home/pi
6. comment out /home mount in /etc/fstab*
7. edit RO/RW mount shell scripts in /opt to support card (un)locking (the sdcard program is in /usr/local/ )
8. reboot in RO
Be aware you will have about 40MB of changes in /home before the system runs out of ram.
However, I'm sure you can rebuild the ramdisk file for your needs, and start purging files you don't need to make the OS smaller.
Best of luck,