IIRC, the 2300 already has support for T-Rex/PCMCIA and IR-Talk in its ROM. The 2300c, the 1400 and the 3400 were developed together and released at the same time, they are all basically the same machine with the same ROM in three different flavors, IIRC.
The IIsi & SE/30 might need some help in that area!
5300's won't work as donors, everything is on the MoBo as was the case with the 3400, not on a DaughterCard like the 1400's T-Rex/Card Cage/IR Subsystems.
It is a parallel project, but one that'd be a lot more
than just ethernet as an add-on, IMHO. :approve: