I'm working on my version 3 board already; will integrate what I learned from version 2 and will include a jumper for the two Mac Portable Versions (as you mentioned above). It will also have a pin to easily route a wire to the PDS for the DTACK. I don't have a backlit but will make the modifications.
https://github.com/2tf2294x4g-maker/MacintoshPortable8MB_RAM_v3
https://github.com/2tf2294x4g-maker/MacintoshPortable8MB_RAM_v3
