There are LocalTalk to Ethernet Transceivers I don't know about support in
NetBSD.  Also I have a IIsi/'030 ethernet card which has a pass through
NuBus port (I think, I've never tried it but the connector looks right.  I
don't know if you could jury-rig two cards into a SE case... If you're
interested I could look up the part number (I don't have it in front of me
right now...)

Brendan